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PRACTICAL DIE-MAKING 



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McGraw-Hill Book Compaq 

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PEACTICAL 

DIE- MAKING 



A COLLECTION FROM THE LATEST 

INFORMATION ON DIES AND 

DIE-MAKING 



COMPILED BY 

FRED H. COLVIN, As. M. E. 

associate editor of the American Machinist, author of "machine shop 

ARITHMETIC," "MACHINE SHOP CALCULATIONS," AMERICAN MACHINIST 
GRINDING BOOK," "THE HILL KINK BOOKS," ETC. 



First Edition 



McGRAW-HILL BOOK COMPANY, Inc. 
239 WEST 39TH STREET, NEW YORK 

6 BOUVERIE STREET, LONDON, E. C. 

1916 



<*:* 



Copyright, 1916, by the 
McGraw-Hill Book Company, Inc. 



lb- " 



/ 



:e maple tress yokk pa 

M -8 1916 
©CI.A418368 



INTRODUCTION 

The best information in any line of work does not come from 
the work of any individual but from the combined experience of 
many. Each contributes his share and the combination gives 
us a far wider range of information than we could secure in any 
other way. So in compiling this book it has been the aim to 
secure facts and examples from many sources in order that every 
reader may find some of the work just suited to his needs. No 
originality is claimed and full credit is given so far as possible 
in the list of authorities in another part of the book. 

The Author. 



L 



CONTENTS 

Page 

Introduction v 

CHAPTER I 

Bending and Forming Dies 1 

A Hand-bending Fixture — Bending a Hook — Hot Bender for 
Forming Hooks — An Interesting Bending Die — Tools for Forming 
Wire Handles — Forming Dies for Milk-can Handles — Ring Making 
in the Punch Press — An Unusual Forming Operation — Forming a 
Small Brass Clip — Forming a Sheet-metal Roll with Hubs — 
Making a Steel Tube in the Power Press — Wiring Pieced Sheet- 
metal Buckets — About Curling Tools — More Curling Tools — 
Seaming Die. 

CHAPTER II 

Punching, Shearing and Blanking 36 

Punching Holes in Block Links of Bicycle Chains — Perforating Die 
for Round Shells — A Piercing, Blanking and Forming Die — An 
Adjustable Cropping and Piercing Die — Punch Press Shearing 
Operation — Punch and Die for two Sizes of Wrenches — Shearing 
Dies for Ball-bearing Cones — Punch and Die for Ratchets — Punch 
and Die with Automatic Spacing Device — A Multiple Hand Punch 
Punching Tool for a Fiber Washer — Compound Die for Celluloid — 
Hot Punching of Forgings — Cutting Two Blanks at each Revo- 
lution — Piercing, Curling ane Cutting-off Die — Press Tools for Tin 
Staples — A Blanking Die and Forming Tool for a Clip — Thickness 
of Blanks — Die for Can Top and Bottom — Tools for Cutting-off 
Angle Iron. 

CHAPTER III 

Drawing Sheet Metal into Various Shapes 70 

Drawing a Difficult Shell in a Single-acting Press — Forming 
Rivets in Soft Sheet Steel Parts — Piercing Thick Stock — Drawing 
Curved Shell — Blanking and Drawing Shells at one Stroke of a 
Single-acting Power Press — Press Tools for Oval Flasks — One- 
piece Pressed Steel Pulley — A Drawing Punch Die — Drawing 
Dies for a Fan Hub — Making a Fuse Clip — Making Sheet -metal 
Boxes — Press Tools for Making a Swivel — Making a Small Form- 
ing Die — Reinforcements for Tapped Holes in Brass — Pressed 
Versus Machine-finished Parts — Making a Pressed-steel Bicycle 
Hub — Hollow Balls from Flat Stock — Method of Making Door 
vil 



viii CONTENTS 

Page 
Knobs — Deep Drawing of Metals — Drawing Brass Shells and 
Other Press Work — Pressure Required to Draw Sheet Metal — Dies 
for a Drawn Copper Shell — Drawing 18-lb. Cartridge Cases on 
Bulldozers and Frog Planers. 

CHAPTER IV 

Press Tools Used in Clock Manufacture 139 

A Subpress Perforating Die — Subpunching Clock Wheels — 
Building a Sectional Subpress Die — Tools Used in Making Eye- 
glass Bridges — Dies Which do not Waste Stock — Progressive 
Drawing, Piercing and Blanking Dies — Double-operation Die — 
Upsetting the Ends of Boiler Tubes — Die for Heading Stay-bolts. 

CHAPTER V 

Data and Suggestions on the Making of Dies 173 

An Interesting Sectional Die — A Reliable and Economical 
Forming Die — A Combined Blanking and Forming Die — A 
Sectional Die Flat that is Easily Made — Making a Difficult Die 
Rapidly— Cast-iron Blanking Dies — A Positive Stripper — Force 
Unnecessary to Strip Work from Punches — Suggestions for Press 
Tool Standards — Laying out Stepped Dies — Method of Holding 
Punches in Place — Relocating Misplaced Punches — Chart for 
Deflections and Loads on Rubber Pads — Chart for Cup Blank 
Diameters. 

Authorities Quoted 195 

Index 197 



PRACTICAL DIE-MAKING 

CHAPTER I 

BENDING AND FORMING DIES 

The use of punches and dies for forming sheets and rods of 
metal has grown to far greater proportion than was dreamed of a 
few years ago, and new applications are being discovered every- 
day. Beginning with the simpler forms, such as bending dies, 
the different types which are in more or less common use will be 
taken up, showing the designs and practice which has been found 
to give satisfaction in shops in various parts of the country, with 
some from English shops as well. A good beginning is shown in 
the simple example given by Fig. 1. 




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Fig. 1. — A simple bending and forming job. 

In Fig. 1 is shown a blank a, cut and pierced by the usual tools, 
not shown here; b is the result of the first bending operation and c 
the finished article. The pieces were made from cold-rolled stock 
0.062 in. thick. Before they were made in the tools shown some 
tools were used which necessitated three separate handlings. 
They were formed as at b, then closed and afterward p]anished. 

Fig. 2 shows a plan of the dies themselves — for there are really 
two dies placed side by side in one bolster. A is the front die 
and B,B the moving parts of the rear dies. C,C are mild steel 
pins which are a push fit in bolster D and in the dies. 

1 



2 PRACTICAL DIE-MAKING 

Fig. 3 is a section on line x-y, Fig. 2, and shows plainly the con- 
struction of the rear die which consists of a piece E arranged to 
receive the sliding members B. It will be seen that when pres- 
sure is put upon the latter they will descend and approach each 
other. Pressure pins are placed beneath them as shown, and also 
a spring to expand them on the up-stroke. The angle of the 
slides is about 15 degrees. 






Fig. 4. 



ud cnr 

Fig. 3. 
Figs 2 to 4. — The dies for bending and forming. 



Fig. 4 gives a side view of the front punch and the which give 
the first bend. 

The illustration, Fig. 5, shows the essentials of a bending punch 
and die for making right-angle bends in sheet or strip stock. 
It is particularly well adapted to long narrow strips which must 
be formed at right angles, and are common in typewriters, adding 
machines, electrical-measuring instruments and the like. 



BENDING AND FORMING DIES 3 

It has always been a more or less difficult problem to make a 
right-angle bend (that is truly a right-angle bend) without a 
farming and bumping operation. This is because the stock will 
spring back after the bend. The bending die as shown, using a 
roll as a means to form the bend, overcomes this difficulty. 
The left-hand side of the illustration shows the punch and the die 
closed at the end of the forming operation; the right-hand side 
their normal or rest position. 

The strip is shown at A, and at B the work after forming, it 
being understood that the bend is to be made on both ends of the 




Making a right-angle bend. 



part. The punch is shown at C and at D the die block and strip- 
per. A movable slide E is held in position by any convenient 
means of gibbing. This movable slide carries the forming roll F, 
and an adjusting setscrew G provides means for taking up for 
wear and varying the pressure in the forming operations which is 
another advantage over the common form of bending die. The 
strippers H remove the formed part from the punch G. The rods 
K extend through the bed of the press to the die stripper springs. 
The work is nested in the position shown at A, and as the punch 
descends the part to be formed is gripped between the face of the 
punch C and the die block and stripper D. As it is carried on 
down past the rolls F they roll the stock up against the punch, 



PRACTICAL DIE-MAKIXC 



effecting an accurate and permanent right-angle bend. The part 
is removed from the die in the usual manner by a die stripper. 

The advantages of this die, as can be readily seen, are the 
increased life brought about through the use of the roll, it always 
presenting new surfaces in the action of the forming operation, 
and the feature of being able to adjust for different pressures as 
well as take up for wear. 

A Hand-bending Fixture. — A method of hand-bending the 
pieces is shown in the fixture illustrated in Fig. 6. These pieces 




A hand-bending fixture. 



are made of No. 26 (0.063 in.) music wire. The length before 
bending is 1 J K6 m - The fixture is made with a tool-steel bend- 
ing-form, piece A, and a gage point for the wire B. The wiper C 
is also made of tool steel and a base D of cast iron. The handle 
E is made of cold-rolled steel and F is an adjustable stop. 

The manner in which the fixture is used is as follows: When 
the wiper C is at rest against the stop on A, the wire to be bent 
is inserted in its slot, gaging with the projecting stop pin in B. 
Then with the wiper it is followed around until the handle E 



BENDING AND FORMING DIES 5 

comes against the stop-screw when the piece will be formed. 
The screw in F permits any adjustment required to suit different 
tempers in the wire. 

Bending a Hook. — The accompanying illustrations, Fig. 7, 
show tools for bending the hook, which as shown, is more than 
a half circle. These tools consist qf the punch A, which fits a 
suitable holder in the foot press, a stationary die B, which is a tight 
fit in the slot H and held in position by screws, and the tumbler 
die C, which is an easy fit in the slot H and located by the pin D. 
The hardened-steel piece E driven into the die C serves both as a 
stop for adjusting the die C to the right height and for a weight to 
bring it back into position after the bending operation. In 





The Work 


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Fig. 7. — A novel hook bender. 



operation the wire is laid across the top of the dies B and C, fitting 
in the grooves and against the gage F as shown at X. As the 
punch descends the hardened-steel pin E, resting against the 
screw G, resists the pressure until it reaches the lower part of the 
die C; the pressure then causes the upper part to tip forward, 
following around the form of the punch A and bending the hook 
as shown, as the punch ascends, taking the hook with it, the 
weight of pin E brings C back into position. The hooks are then 
knocked off by a spring knock-off fastened to the stationary part 
of the press while the operator is putting another wire in position. 
A girl can do 100 gross per day with these tools. 



6 PRACTICAL DIE-MAKING 

Hot Bender for Forming Hooks. — The bending machine shown 
in Fig. 8 is of a novel form for forming hooks out of ^{q-iu. hot 
steel. The full lines in the illustration show the position of the 
moving parts after the hook is completely formed. The initial 
position of these is shown by the dotted lines. The stock is 
placed in as at Q and is acted upon by the bending pins K and P 
on the segments A and B, which are rotated by the downward 
movement of the racks F and G. The initial bend at the left- 







Forming hooks hot. 



hand side of the hook is produced by the downward action of the 
upper die D, which is forced downward by spring pressure preced- 
ing the action of the racks. The centers for the segments A and 
B are mounted in a casting which forms one piece with the lower 
die C, but which for the sake of simplicity is not shown. Since the 
stock is worked hot, the pressure furnished by the spring on the 
upper die D is sufficient to prevent the work from slipping or 
pulling. 

An Interesting Bending Die. — A die made to bend the arms on 
item plates used in the adding machines manufactured by the 



BENDING AND FORMING DIES 7 

Duco Adding Machine Co., St. Louis, Mo., is shown in Fig. 9. 
One of the parts may be seen in the foreground. 

It is important that the arms be bent without being stretched, 
so they may fit into the mechanism without trouble. For this 
reason the die is different from the ordinary bending die. The 
piece to be bent is laid with the center hole A over the locating 
pin B, with the arm between the two pins C and extending over the 
V-block of the die. As the upper portion of the die descends, the 
member on which the item plate is located is pressed downward, 
swinging on the hinges D until it strikes the surface E. This 
beveled surface is parallel with the surface F of the V-block, so 
that the two bends produced are right-angled. 

If the upper die were the ordinary rigid kind, the bends would 
be severely stretched, and the distance from the center hole to the 




Bending dies for adding machines. 



first bend could not be depended upon, as slippage or difference in 
density of the metal would make considerable error. To allow 
for this, the member G is hinged at H and is kept against the stop 
I and away from the part J by a spring, when in normal position. 
As the upper part of the die descends, the spring allows the 
member G to swing toward the member J and compensate for the 
movement of the metal being bent. This type of die gives 
extremely accurate results, no trouble whatever being experienced 
in obtaining interchangeable parts. 

In order that the parts of the subpress will always be put to- 
gether correctly, the posts on one end are set closer together, so 
that it is impossible to get the upper part on the wrong way. 



8 PRACTICAL DIE-MAKING 

This method is followed on all the sub-press dies used in the 
shop which is superior to the method of using posts of different 
diameters, as is often done. Where different sizes of posts are 
used it is necessary to keep separate diameters of bar stock and 
also use another set of tools for finishing the holes. This is, of 
course, more expensive, not only in that extra tools and stock must 
be used, but because more time is taken for the work that must 
be done on both the punch and the die plates. 

Tools for Forming Wire Handles. — The sketches show the 
two pairs of tools used for making the wire handles shown at A, 
Fig. 11. The first operation and the tools which form the straight 
wire into staple shape, are shown in Fig. 10. The wire was cut 
and the ends rounded; in this operation, care must be taken to 



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nc 



Fig. 10. — The first operation. 

have the wire finished exactly the length required to fill up the 
impression for the ears in the die E, Fig. 11. The length can 
only be accurately obtained by experiment after both pairs of 
tools are finished. 

Having ascertained the right length of wire, the two adjustable 
screws B, Fig. 10,' must be set and locked with the nuts provided, 
being careful to have both sides of the staple come the same length, 
the corners of the die must be well rounded and polished and be 
exactly the same shape to insure the wire drawing down evenly 
on each side. The use of three short pieces of wire will facilitate 
setting the tools; the two upright wires should be free enough 
to be easily moved by hand. 

The press must be so set that it will give a sharp blow, the 
groove in the bottom of the die being left shallow to allow the 



BENDING AND FORMING DIES 9 

punch to hit the wire, which will result in throwing the ends of 
the staple slightly inward, not sufficiently to make it cling to 
the punch, but enough to set it so as to enable it to be easily 
withdrawn from the die. It is well to use oil in this operation. 

When making these tools a special cutter was' made for the 
grooves and used on the miller; this did a good, quick job. The 
punch and die are hardened and the temper drawn, leaving 
the bottom of the die rather softer than the corners, which have 
to withstand the most wear. 

The second operation is shown in Fig. 11. It consists of bend- 
ing the staple-shaped wire into the required shape for the handle, 








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qpnpr^ 






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Fig. 11. — Bending the ends. 



and flattening the two ends. The punch is omitted on the plan, 
which shows the die ready to receive the staple-shaped wire shown 
by the thick lines C, held in position by the sliding piece F, which 
is actuated by the lever B. The success of this operation de- 
pends upon the result of the first operation. The die has to 
withstand a backward thrust, which is resisted by a strong 
back of the bolster, which must be bolted down tightly to the 
press, the staple must be held well into the die by the piece F and 
the cam must come up on the center so that the considerable 
thrust forward caused by bending the wire will be taken by the 
pivot D and not have a tendency to move the hand lever B. 
The punch and die, the piece F and the cam end of the lever B, 



10 



PRACTICAL DIE-MAKING 



are hardened and slightly drawn. These tools produced a good 
article, are simple to make and operate, and stood up well. 

Forming Dies for Milk-can Handles. — The show room of the 
Taylor & Challen Co., Ltd., Constitution Hill, Birmingham, 




Eng., contains many extremely interesting samples of sheet- and 
rod-metal stamping and forming. 

Among the interesting die work is the making of handles for 



BENDING AND FORMING DIES 11 

milk cans, these cans being different from our own in both shape 
and capacity. The cans are tall, much smaller at the top than 
the base and are said to hold 20 imperial gal., though usually 
filled with about 17 gal. on account of weight in handling. The 
handles for these are made by the dies shown in Figs. 13 to 17. 

The first operation cuts the rod, Fig. 12, which is about % in. 
in diameter to length as at A, the ends being turned down as at 
B, by the dies shown in Figs. 13 and 14. 

The upper portion is shown upside down as in Fig. 13, the base 
being in halves as at C. At each end is a steel punch D, held 
by setscrews and adjusted by screws between the ends and the 
holder C. 

The lower die is shown in Fig. 14, the cover plate being removed 
from the left side to show the rollers beneath. Three V-shaped 
holders E, set at right-angles, carry hardened-steel rollers F, 
each having a small axle. The plates hold them in place, the 
opening shown guiding the rods to be bent. 

The ejector is connected to the plate, this being supported on 
four rods which are guided in the bolster and forced upward by 
the four springs shown. The ends are heated before bending. 

The Third Operation 

The third and final operation in producing the finished handle 
is accomplished by the dies shown in Figs. 15 to 17. The bar 
with bent ends is put in place as shown, the ends resting on the 
outer supports, which give tfie proper angles to the ends as re- 
lated to the other bend. 

The curved block A is forced down ahead of the ram itself, 
bending the rod between the rolls in the ends of the arms B,B 
and against the bottom block C, as in Fig. 16. Then the ram 
itself comes down and the wedges D,D begin to act on the side 
arms B,B, forcing them in and bending the ends over, until the 
handle is completed in Fig. 17. The handle itself is shown in 
Fig. 18. 

Tool for Forming Eyes in Wires. — The tool shown in Fig. 19 
was designed for forming an eye on the ends of wires in cases 
where the production did not warrant making forming-machine 
dies; the cost of bending had to be nominal and the eyes of certain 
required dimensions. 

The tool has a base block A, to which is fastened with spacers 



12 



PRACTICAL DIE-MAKING 



a cover B. The straight wire is pushed between the pins D and 
E against the adjustable stop C. The two pins are driven in a 
gear F meshing with a segment G, provided with a handle and 
pivoting on J. A spring K always brings the handle back against 
a stop pin M in the position shown. 

By turning the segment, the eye is formed and by bringing 
the wire against the guide H, the eye is brought on the center of 
the wire. This latter can then be taken off while the handle is 
released. With some practice, a boy can produce 400 eyes an 



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Fig. 19. — Die for bending eyes. 

hour. The plug L allows gears with different sizes of pins to be 
easily inserted. 

Ring Making in the Punch Press. — The accompanying illus- 
trations, Figs. 20 and 21, show a pair of tools for the punch press. 
They produce at one blow a ring that it formerly took two blows 
to form, and as the second operation was done in a pair of toggle 
tools, the stripping from the punch was done by hand. Thus the 
tools shown effected a big saving. 

The cycle of operations was follows: The stock, which was of 
soft brass 0.378 in. wide by 0.031 in. thick, was fed by the opera-, 
tor, through the slot A, up to the stop B. The punch in descend- 
ing cut off the blank with the cutting edges C. At the instant 



BENDING AND FORMING DIES 



13 



the stock was severed the mandrel D bent, or raised the blank 
into the form of a U. The mandrel D was mounted in a sliding 
piece E which, as the mandrel reached the bottom of the die, 
recedes into the punch proper F, thus allowing the punch to 
gather the ends of the blank together and complete the rounding 
of the ring. 

On the upward stroke of the press the ring is stripped from the 
mandrel by the spring-actuated stripper G. This is actuated, as 
shown by the two plates H which are fixed at the back of the bol- 




Fig. 20. — Dies for bending rings. 

ster /. The incline of these plates engages with the horns of plate 
/ and so makes the stripper travel forward on the upward stroke 
of the press, and backward on the downward stroke. As the 
rings were stripped from the mandrel they dropped into a chute 
which led to a pan under the press. 

Inspection will show that the slot A through which the stock 
was fed, is formed in the upper part of a plunger. By this means 
the stock was held as in a vise during a greater part of the stroke, 
and could only be fed forward when the punch was on the upward 
stroke and the stripper was about to commence the stripping 



14 



PRACTICAL DIE-MAKING 



operation. This slot was the only gage or guide required besides 
the stop B, and it was this plunger which allowed the press to 
run continuously. The operator's only business was to feed 
the stock forward. 

The die was made, and the cutting members as well as the stop 
B, were screwed to it, as shown, to facilitate grinding and repairs. 

In like manner the punch proper, of tool steel, was screwed 
to the punch holder, of mild steel, and the cutting member of the 
punch was screwed to the punch itself. 




Fig. 21. — The punch and former. 

An Unusual Forming Operation. — The forming of the piece in 
Fig. 22 was completed in two operations. The first operation 
was bending the four ears at right angles to the body of the 
part and also forming the slight radius between the ears. The 
second operation was forming the piece as shown, making three 
distinct bends; this was accomplished by using a novel method of 
attaching the ram to the punch holder instead of the usual method 
of making the side ram a part of the die; the upper right-angle 
bend is made by the swinging ram, using the top of the punch 
as a forming die. 

The construction and operation of the tool is shown in Fig. 23. 



BENDING AND FORMING DIES 15 

The swinging ram A first strikes the angle block B; the tension of 
the springs C is sufficiently stiff to cause the ram to ride up the 
angle, allowing room for the work to pass it, and after forming 
the right-angle bends, the blocks D strike the hardened steel 
plugs E pushing the forming plate F down and keeping it in con- 
stant relation to the punch. The swinging ram is now pushed 
forward by the pivoted cams E striking the cam blocks H. At 
the end of the stroke the swinging ram is in a horizontal position, 
one end resting on the stop face of the angle block A, the other 
end forming the work. A knockout device was added which 
pushed the work from the punch. 

Forming a Small Brass Clip. — The brass clip shown in Fig. 
24 is formed complete in one stroke of a single-acting press by 
the punch and die shown in Fig. 25. As will be seen, three down- 




Fig. 22.— A difficult bendin 



ward bends are made and one upward. The blank is located by 
the pin A and the set edge B. The stud C is flatted, as shown in 
the end view and carries the locating pin A. The semicircular 
piece D for forming the upward bend is an easy sliding fit in the 
forming-die block E. 

The punch descends, forcing the clip down over the stud C for 
the first bend. Further descent compresses the spring H back 
of the punch J and bends down the sides M. Then the pro- 
jection G on the punch strikes the piece D and forms the upward 
bend, as shown in the end view. 

Forming a Sheet-metal Roll with Hubs. — In operation No. 1 
in Fig. 26 is shown one end of a formed-up sheet-metal roll with 
hubs formed as an integral part of the roll, and also the operations 
necessary for completing the piece. As this was only evolved 
after various forms were tried, such as solid rolls turned in the 



16 



PRACTICAL DIE-MAKING 




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BENDING AND FORMING DIES 



17 



automatic screw machine, and rolls made by cutting off lengths 
of tubing into the ends of which turned steel plugs were swaged, 
it is quite certain that for some purposes this represents a roll 
which is highly satisfactory from a point of cost. 

The blanking dies used are shown in Fig. 26, each length of 
roll having its own die. The only points worthy of note on this 



O 



0.045 Brass 




Fig. 24.— The clip to be bent. 

die are the tool-steel face welded to the soft-steel base plate, and 
the method of holding back the spring stripper sufficiently to 
allow the punch to be inserted in the die freely while setting up. 
This is accomplished by the hooks A, the stripper plate being 

H 




Fig. 25. — The dies used. 



forced back in a vise while the hooks are inserted and pried out 
after the set-up is completed. 

These dies for the first operation were designed with a spring 
stripper so that the scrap from another job, which was of irregu- 
lar outline, might be used. As this scrap was not of sufficient 
amount, or a regular output, the die shown was also made to use 

2 



18 



PR A C TICAL DIE-MA KING 



a solid stripper and rear guide, with stock sheared to the proper 
width, the spring stripper then being removed. 

In Fig. 27 is shown the die which is used for the second and 



OPERATION NO.I 



,16 Oage= 0.050 




OPERATION OPERATION 

NO.E N0.3 



a 



FlG. 26. 3LANKIN0 PUNCH AND DIE OPERATION 






fe 



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OPERATION NO. 2 N0.5 

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Bib IB 
sib 

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iking 




FORMING PUNCHES AND DIE OPERATION N0.E&5 
Fig. 27. 
Figs. 26 and 27. — Forming a sheet metal roll. 

third operations, with separate punches for the two operations; 
there are several points in this die worthy of note. 

To take care of two sizes the ends and center of the die are 
made in sections fitting into the cast-steel die and set up solidly 



BENDING AND FORMING DIES 



11) 



together by means of the end set-screws, a filler block B being 
used when the short section is in the die. 

The spring strippers below are removable, as they cannot be 
used for the second operation of forming. 

The same punch holder is used for the punches of both opera- 
tions and both sizes. To facilitate setting up the die in align- 
ment with the punch, a solid turned roll is used (not shown) 
for the last operation and the punch brought down upon it. For 
the first operation of forming, a formed blank is used to align 
•the punch and die, as usual, and to locate the blanks the ordinary 
method of a plate with a hole shaped to fit the blank is employed. 

It may be stated that these rollers were (and probably are) 
used in the shelving of a metal case for heavy, large office books, 



■6 

i 



T/x 



IB 



FIRST OPERATION 



gffo/es *t[" 



m 




SECOND OPERATION 



K--/I?— x 



Fig. 28. — Making a tube in two operations. 



to prevent the sliding and consequent wear on the books and the 
manual labor of shoving them in and out on closely spaced deep 
shelves. 

Making a Steel Tube in the Power Press. — The tube illus- 
trated is made of 16-gage hot-rolled steel and has three 2 ^ 2 -i n - 
holes in one end. When finished, it is used in a muffler for auto- 
mobiles. It must, therefore, be strong enough to withstand 
the constant shocks and vibrations from road use as well as the 
compression it is subjected to by having the caps pulled up against 
the ends by a %-m. bolt. 

The holes in the tube are equally spaced and must be accurate 
in position to correlate properly with the other holes, and for this 
reason a compound blanking die and punch is used. 



20 



PR A C TICAL DIE-MA KIN( ? 



It will be noticed that the blank is slightly turned on both 
edges, as shown at.X, Fig. 28. This is done by having a 2-in. 
radius ground on the blanking punch, as shown at X, Fig. 29. 
This curve gives the blank a start when curling, which is neces- 
sary where a perfectly round tube is desired. It also gives the 
joint the desired V-recess to receive the brass when being brazed 
in a later operation. 

The compound blanking die and punch is very simple and 
strong, and under ordinary conditions will last a long time. The 
punch is seated in the shoe A . The die shoe is at B. The shoe A 





c 








D 






s 










Vf *'< ¥• 


A 










i&S! !h| itfi IH| III; 

X\6\ 1 : 16! I i leixj 








^ 




_. i 
















\ 


\ 






c 


R 












1 L ^ 




L rs lJ 






K 






! J 

1 


ii it !i__:> ;I__;:l 


6 




1 

it 


r _i__ i — ^p-i- L -%-p 

--, i-rjrij-T--7 _ >,-t;-i--T- 

i i H ijj i Q i i 






l! ! ' l J' ;: , ,ii 


) 

> 








I i | i» 






i i n 





Fig. 29. — Blanking die and punch 



is made of cast steel — strength being desired with as small a size 
as possible. The die shoe, which is larger, is made of cast iron, 
not having a high unit stress. 

The punch, instead of having the common stud, has a solid 
head C, with bolt holes D which secure it to the press ram in such 
a way that it cannot pull or twist and cause shear. 

The end view only of the blanking die and punch is shown. 
The punch and die is 14 l & in. long. It has been proved that a solid 
head C and the guide pins E on this type of press tool give them 



BENDING AND FORMING DIES 



21 



longer service and less die trouble, with the advantage of being 
easier and faster to set up. 

The punch V is made of hardened tool-steel and is seated in the 
shoe A. It is held in position by nine %-in. fillister-head screws 
F. Three of these screws secure the three perforating punches G, 
which are hollow-ground to prevent slugs raising out of the die 
by sticking to the punch. The blanking punch V is coun.terbored 
to seat the two stripper pins H, which have the springs / strong 
enough to release the work from the perforating punches G. 
These springs have the punch shoe A for backing. 




FRONT ELEVATION END ELEVATION 

Fig. 30. — The second operation die. 

The sectional die J is made of hardened tool steel and is seated 
in the shoe B. The pressure pad K in the blanking die has the 
three bushings L to correspond with the perforating punches G. 
This pressure pad has a perpendicular motion of % in., which is 
necessary to release the blank. The required motion is supplied 
by the rubber bumper M. 

The bumper If is 6 X % in. and is held in position by the bolt 
N and the plates and P. The knockout pins Q are hardened 
tool steel. The steel is stripped from the punch V by the stripper 
R, which is open in front to allow the quick removal of the blank. 
The stripper is held in place by the six fillister-head screws S. 



22 PRACTICAL DIE-MA KING 

The guide pins E are ground to force in the shoes B and secured 
by the headless screws T. They are hardened and have oil 
grooves for proper lubrication. 

The second-operation die and punch is shown in Fig. 30. This 
die and punch must be held as securely as the blanking die 
and punch. It has a solid head and guide pins, with a lead E on 
the die. 

The punch C is hardened tool steel and is set in the shoe A, 
being held in position by the screws D. The die E is hardened 
and set in the die shoe B. The blank F, as shown, is curled 
around the arbor G, which revolves in the bearings H when the 
punch descends. The bearings / are chamfered to permit the 
free removal of the arbor G. 

When the blank F starts to curl, the arbor has a tendency 
to raise, and the lever J is used to prevent it doing so. The 
spring K serves to hold the lever J in position while in operation. 

The plates L are fastened on the end of die by the screws M 
and the dowel pins N. They act as bearings for the arbor G 
and as gages for the tube F. 

Die for Forming a Tube in One Operation. — This die consists 
of the bedplate A suitable for the press at hand; the die B, the 
mandrel C, the punch P and the cast-iron punch holder E. 

Fig. 31 shows the punch up with the blank dropped in, and 
the mandrel in position. The weight of the mandrel has a tend- 
ency to crowd the blank over against the punch and allow the 
mandrel to start in the die. If the blanks are placed in the die 
with the burr in toward the mandrel there is no tendency to 
buckle back. 

Fig. 32 shows the die in the closed position and needs no 
further explanation. Figs. 33 and 34 show the style of tube 
which has been made by the hundred thousands in this die. The 
little ears that lock it together pass in the grooves in the die shown 
by the dotted lines in Fig. 32. The blanks are dropped in the die 
with the ears down and formed as a plain tube would be, except 
that the ears are left out at the first stroke as shown by the dotted 
lines in Fig. 33, after which the mandrel is turned with the tube 
until the ears are standing up and struck another blow, which 
closes the ears in position. 

This die will form a tube ^ in. thick or less and there seems to 
be no reason why it would not operate with any gage. Tubes 8 



BENDING AND FORMING DIES 



23 



and 10 in. long, of XX tin 3^6 an d % in. in diameter inside 
measurement, have been made in this die. 

The open front is very convenient for feeding blanks and a fork 
can be used at one side of the die to pull the tubes off the mandrel. 
It is more convenient to lift the tubes out of the die with the 
mandrel, pulling them off outside, than to remove the mandrel 
while the tube is in the die. 




Fig. 31. 
Figs. 31 to 34, 



Fig. 32. 
-Dies for forming a tube. 



Punch and Die for Small Tubes. — The die shown in Fig. 35 
has given excellent results in piercing rows of holes in a small tube. 
The details are self-explanatory. The die nest should be adjust- 
able to take the strain off the die and be lowered after piercing 
each row of holes in order to easily index the tube. 

Wiring Pieced Sheet-metal Buckets. — It is customary to do 
this operation on what is called an open-face or horning press, 
equipped with a knee and table slide. When using this, the oper- 
ator is compelled to push a heavy die, fastened to this slide, under 
the punch, which, after wiring, has to be pulled out again to re- 
move the wired body and insert another. As these operations 



24 



PRACTICAL DIE-MAKING 



are repeated constantly all day long the operator is apt to be 
played out, when the day is done, by this hard and heavy work. 
To increase the output without fatiguing the operator the 
arrangement here outlined was designed and built. The principal 
mechanical feature involved is the use of the Geneva stop for 
the intermittent action of the large table on which the dies were 
placed. 



$ Punch fact 




Punch 6uicfe 



o 



o 



w 



'■!> 



3j 



<!■ 



o 



Lock with Spring 



O 



Fig. 35. — Punch holes in small tubes 



The horning press above referred to forms the nucleus of the 
whole proposition. The outfit is shown both in detail and 
assembled. The changes made are shown without any attempt 
to portray the exact appearance of the slide of the press itself, 
which is standard and has a 3-in. throw of crank to allow the table 
to swing in and out as the punch descends and rises. 

The press is mounted on a special base A, Fig. 36, also shown in 



BENDING AND FORMING DIES 



25 




< 

I czd j| (zzi Ij i n 

! CZD jf-CZZD I I I 








26 PRACTICAL DIE-MAKING 

the detail drawing. The table support B is fastened to the face 
of the press and secured to and supported by the outside leg C, 
which in turn is fastened to the base A. On the top of B is the 
round disk D, which has a ball-race for 1-in. balls, enabling the 
large circular table E to turn readily. The disk D is fastened to 
the supporting table B from below by capscrews. 

The table E is machined as shown in the detail and has a large 
hole through the center at E-l, into which is inserted the large 
bushing F, which is fastened to the table E by capscrews and dowel 
pins. The bushing F has a square shaft hole F-l in the center. 
The table E is further provided with an extreme outside riding 
edge on the under side, E-2. In addition it has the ball-race £"-3, 
which matches the ball-race D-l in the disk D. It is supported 
nearest the press face and dirctly under the slide of the press and 
takes the pressure when the punch is curling the metal around the 
wire. Two brackets G with a taper roller G-l support the table 
E. The brackets G are fastened to the patches B-l on the top 
side of the table support B. 

The Dies 

As six dies Z are used, there are the same number of holes in the 
face of this table E, marked E-4. They are equally spaced and 
correctly located to bring each die in position. All the bases of 
the dies have a boss Z-l, which fits in Z. The six dies are each 
bolted to the table by two capscrews. Around the outside rim 
of the table E are six projections £"-6 used, as will be explained 
later, to regulate the swing of the table. 

The shaft in connection with this has a square end as at E-l, 
which fits closely into the large bushing F and is held in position 
by a large flanged screw at the top end. This shaft E-l revolves 
in a long bearing B-2 in the table support B, and on the bottom 
end is attached the Geneva stop wheel H, which is a steel casting 
machined with six slots H-l and six arcs H-2 to connect with the 
pin wheel J, which is also a steel casting. The Geneva stop wheel 
is secured to the shaft E-l by a key and taper dowel pin. 

The pin wheel I is machined and has a roller as at 7-1 that slides 
in the slot H-l of the Geneva wheel, and has the outside turned to 
the arcs 1-2, so that when in position it will just turn in the arcs 
H-2 and form a positive centralizing stop for the large revolving 
table E. This pin wheel I is attached to the shaft 1-3 by both 



BENDING AND FORMING DIES 27 

key and taper dowel pin, and has a long bearing B-2> in the table 
support. It is further supported by the bracket J, which is 
fastened to the face of the press and is also detailed. 

At the lower end of this shaft 7-3 is attached a steel miter gear, 
which is the first of a series, and meshes with a similar gear on the 
horizonal shaft K, which runs in a long bearing L fastened to the 
base A. At the other end of this shaft K is another miter gear, 
which in turn meshes with a gear attached to the vertical shaft 
M, which is held in position and runs in the bearing N, also 
fastened to the base A. On this shaft M is attached the brake 
cam 0. This actuates the fiber-faced brake attachment P, 
which comes into contact with the outside periphery of the large 
table E. Two spiral springs hold this brake attachment and the 
roller P-l against the cam 0. 

The shaft M has an upper bearing Q (also shown in detail) 
fastened to the inside of the walls of the press. On the end of this 
shaft is another steel miter gear, which in turn meshes with the 
miter gear fastened on the shaft R. This has its bearings in the 
machine proper, and projects through on the left-hand side of the 
machine far enough to attach the large spur gear S-l, which is 
meshed with the idler gear S-2 and in turn with the spur gear $-3, 
which is the same size as S-l and is directly attached to the 
crankshaft of the press itself. The original flywheel of the press 
itself has been converted into a large spur gear T as shown, and is 
connected to the main shaft U of the machine. This main shaft 
runs in bearings at the top and has a small pinion mounted on it. 
It extends beyond the rim of the large gear T and is equipped with 
a tight-and-loose pulley, not shown. 

The Operation 

The action is as follows: The main shaft U gives momentum 
to the large gear T and turns it at the rate of 18 r.p.m. When the 
clutch is released, this large gear T carries the crankshaft of the 
press with it, and as the large spur gear $-3 is attached to this, 
the movement is carried right through the chain of gears. As the 
last gear is attached to the shaft of the pin wheel I, it is revolved 
and the roller enters the slot in the Geneva stop. This is directly 
attached to the shaft of the revolving table, and swings the wheel 
and table a sixth of a turn and puts the next die in position. To 
overcome the great inertia of the heavy table with its six large 



28 PRACTICAL DIE-MAKING 

dies F, the six projecting lugs £"-6 on the outside rim come in 
gentle contact with the brake control. The cam of this in 
operating pushes the shoe forward, causing it to exert a slight 
but constantly increasing friction to overcome the swing of table. 

When the table is almost in position the pressure is suddenly 
released, and the table is gently and without jar brought up 
against the edge of the brake shoe. The ram of the press has 
been descending all this time, and shortly after the table has 
become stationary the punch goes through its functions of 
wiring. As it lifts and clears the top of the die the action is 
repeated, and as the treadle of the press is locked the machine 
keeps on working constantly. 

Two boys are required to operate the machine, one to take out 
the finished bucket and drop in the new one to be wired, and the 
other to place the wire in position. 

This machine has proved successful in every way. The output 
of the two operators has been increased from 2400 buckets, by 
the old method, to from 9000 to 10,000 buckets a day by the new 
without any hard physical labor. 

About Curling Tools. — Tools used for curling work, under the 
press, have a variety of forms, the simplest type, those for curling 
hinges, being, generally speaking, the least satisfactory. Take 
for instance a tool for curling the hinge shown in Fig. 37. The 
usual type of tool described in text-books for doing this kind of 
work is shown in Fig. 38 and is simply a block having a hole A 
drilled in it, and with a slot B shaped through to admit the hinge 
blank. The drawing of the hinge, which is shown with the tool, 
will most likely show the curl nicely tucked in as at C, Fig. 37. 

However, the usual method of using such a tool, that is, by 
placing a blank in the tool and bringing the press down on it, 
will not give a curl as shown. The result will be as at D, Fig. 
39, where it will be seen that the leading part of the curl has 
refused to curl. The reason for this will be clear if we con- 
sider the enlarged section shown in Fig. 40. In this class of 
work the stock is never very flat and to get the blanks in and 
out of the tool easily it is usual to have the stock slack in the 
slot. The consequence of this is that when the blow comes, 
the blank is leaning over slightly and the piece takes its first 
bend from the point where it touches, as at H, Fig. 40. Hav- 
ing started to bend here, the leading portion will have nothing 
to cause it to bend afterward unless, of course, it is being formed 



BENDING AND FORMING DIES 



29 



round a pin. A simple way of preventing this, and one that 
will assure a curl that is closely tucked in, is to have the hinge 
blanking tool ground off at the corner so as to give a reverse 
shear at this point. That is, there will be an initial bend at 
this point. 



Fig. 37. 



J3 



Fig. 38. 



D -Y\ 



Fig. 39. 




Fig. 40. 





Fig. 41. 



Fig. 42. 



Top 



LP 



IT- 



Bottom 



Blanking Tool 



Fig. 44. 



1 ) 



Fig. 43. Fig. 45. 

Figs. 37 to 45. — Details of curling tools. 

A specific case which happened some years ago will serve to 
illustrate this point. Designs came down into the shop for 
tools to curl the hinge shown in Fig. 41. The tools as designed 
are shown in elevation in Figs. 42 and 43. The idea was to 



30 



PRACTICAL DIE-MAKING 



place the blank on Fig. 42, bend it and then complete the curl 
with the tool shown closed in Fig. 43. This pair of tools made 
a very poor curl and it was decided to put in another tool to 
give an initial bend to the end. Instead of this, however, the 
blanking tool had the ends ground off as shown at E, Fig. 44, 
with the result that the blank when punched was as shown 
atF. 

The top tool of Fig. 42 was then cut away as at G, Fig. 45, 
and the first bending operation left the piece as shown. From 
this tool it was removed by sliding off, and the tool shown in 
Fig. 43 then made a completely satisfactory curl of the hinge. 




vy. 



Fig. 46. — A point in curling metal. 



A point in roll hinge making which may also be used in other 
curling operations is to start with the blank as shown at A, 
Fig. 46. Then a die similar to B will roll the edge without 
the use of a wire inside to keep it round. This obviates the 
necessity of removing the wire which often binds. 

An Adjustable Curling Chuck. — The tendency of packers 
who put up staple articles in tins is to have the top end of the 
can body curled or beaded inwardly, so that the user will not 
run any danger of injury on a sharp, rough edge. 

The device shown in Fig. 47 is an adjustable header or flanger 
for round-can bodies, either pieced or seamless, straight or 
taper, and is so arranged that all sizes of cans within its capacity 
can be made, either beaded or flanged, internally or externally 
as desired. 



BENDING AND FORMING DIES 



31 



Should the pieced bodies be formed too large or too small, 
they can be corrected in the rolling operation so that the cover 
will fit. 

At a is the normal pieced can body, the top curled inwardly 
and walls straight so that the cover may be slipped on easily. 

At b is another style where the head is curled outwardly 
and the cover fits inside: this is used on coffee and tea pots, etc. 







,E 


> 




^-"- \ 




1 ~---^ 


/^ '''' ^ 




! \ \\ 


// B ,_.-- \ 




JV \ \\ 


I L -"'''' -""- 




Li ' E / 


V - - 


i 


m. os 


C) 


KJ ^ft 


It 


X ^ 1 \ '< 


<-y, 


1"" ^'£7 

r — ©7-7 




\\ \ i 




/ 

i /x 


B 





Regular body Regular body Regular body Imperfect body Imperfect body 
curved inwardly curled out flanged out spread at top choked at top 



Fig. 47, 



to size 
-An adjustable curling chuck. 



At c is a can body flanged outwardly ready to have the bottom 
double-seamed. 

At d is shown how the body has been made too small and in 
curling is opened out to the proper size so that the cover will fit. 

At e is shown the reverse, in that the body is made too large 
and is choked in and brought to size. 

An adjustable device for this purpose therefore has its ad- 



32 Practical die-making 

vantages, as it can be made to accommodate itself to all con- 
ditions of previous operations and corrects work that would 
otherwise be defective. 

The device is usually screwed on the spindle of a lathe or 
double seamer and can be operated in either a vertical or hori- 
zontal position. It is shown assembled with the rollers spread 
to the largest size it will curl. The back or spindle plate A is 
cast iron, machined all over and has a thread to fit the spindle 
nose. It has a shoulder on the face which fits the top plate B; 
several fillister-head screws secure this to the top plate B. 

The top plate B is also cast iron, machined all over and recessed 
to fit the spindle plate A. On the face are T-slots cutting it 
into quarters. In these the roller brackets D slide. In the 
bottoms of these are clearance slots for the bracket studs and 
rollers E. On the outside rim is an adjusting slot through 
which the cam disk C is actuated. Headless setscrews hold 
this cam disk C from shifting when set and in operation. 

The cam disk C is made of machinery steel finished all over. 
The outside fits the recess in B. It is just thick enough to turn 
freely when the spindle plate A and the top plate B are fastened 
together. There are four curved milled cam slots. These are 
used in connection with the studs and rollers E which actuate 
the curling-roller brackets D. On the rim are two holes for the 
adjusting pin which moves the disk back and forth to locate to 
the proper diameter the rollers held in the brackets D. 

There are four roller brackets D made of machinery steel and 
machined to fit the T-slot in B. The bottom is drilled and 
tapped for the stud E. The projecting lug is slotted for the curl- 
ing rollers and is drilled for the roller pin. There are also four 
steel studs and rollers E. The roller only is hardened and 
ground. 

The curling and flanging rollers F are made of tool steel and 
hardened. They are so arranged that both internal and ex- 
ternal curling of a beading can be done. The inside wall is 
curved and allows the roller, when used for external curling or 
flanging, to clear itself and not cut into the inside wall of the can 
body. 

The assembly shows the rollers set for inside beading. If 
an outside bead is required, the rollers are turned and adjusted 
to the proper diameter of the can body. This same rule applies 
to the flanging operation, either inside or outside. 



BENDING AND FORMING DIES 



33 



In connection with the curling chuck which is constantly 
revolving when in operation, a stationary tailstock plate or 
treadle disk is used. The face of this is arranged in a series 
of steps to fit the various sizes of cans and centers them for the 
revolving rollers. The can body itself does not revolve. 

A modification of the above device is adopted for wiring such 
articles as garbage pails, ash cans and buckets of every description. 



Fig. 48. 



( ^ 



HMMM^J 



Guide for Punch 




U \r 

Fig. 52. 



Fig. 49. 




s 




(d) 


Hinge 


£*- ^-T 




B-X3 I ; J D 1 1 o 
A-k- ' — ' 




,„*-» "T^R-^ 




LJ 




VI 





Fig. 53. 



Fig. 50. 

Figs. 48 to 53. — Several curling tools. 



More Curling Tools. — The steel stamping shown in Fig. 48 
has four prongs, which require to be curled round as shown at 
B; all four are curled at the same stroke of the machine, one 
which has been used in our shop for several years. In blanking 
out, the stamping is given just a slight bend at the end of the 
prongs, as shown at A, Fig. 48, to give the curling tools a start. 
The tool is shown in plan and elevation in Figs. 49 and 50, re- 
spectively. The main part is an angle plate bolted to a con- 
venient stand, not shown, which has two strips C,C attached to 
the front, in which slides the plate D. 



34 PRACTICAL DIE-MAKING 

This plate is raised and lowered in the guides by means of 
the lever E, which is attached to the eccentric pin working in 
the slot F cut in the plate D. Underneath the slide D a guide 
for the four punches G is bolted to the angle plate. The punch 
guide is slotted to receive the punches, so that they line in the 
same plane as the prongs of the stamping to be curled. The 
guide is shown in Fig. 51. It will be noticed that the slots do 
not come right through the plate, so that the punches are kept 
back against the angle plate. Each of the punches has a pin 
fixed in it as shown in Fig. 52. This pin works up and down 
in the slot shown in Fig. 51, and serves to lift the punches up 
when the lever is raised, which is accomplished by the two 
small plates / fastened to the plate D in Fig. 49 catching against 
the pins. The stamping is held in the cradle H against the 
angle plate. To work the machine, the stamping is simply 
placed in the cradle with plenty of grease and the lever is pressed 
down, thereby forcing the punches down in the grooves and the 
punches curl the ends of the prongs over. When the lever is 
raised, the punches rise also and the stamping is released by 
the punches. 

A Hinge Tool 

Another tool for making a hinge is shown in Fig. 53. This 
tool is used at the blacksmith's fire for making a hinge out of 
1% X ;Hr m - i ron - The blank is given an initial slight bend 
as before and is then heated to nearly a white heat and placed 
between the guides A,A against the stop B. The tool is then 
forced down by the hand lever and curls the plate easily. When 
the lever is returned to its original position it knocks the hinge 
out automatically by rolling it over on the curled part in the 
tool. 

An enlarged view of the end of the tool is shown at C and a 
plate is fixed across the guides A, A as at D to prevent the tool 
from rising up. 

If a plate is required to be curled at both ends, this can easily 
be done by having two levers, similar to the one shown, working 
at either end, or it would probably work if one of the tools were 
fixed to the plate and the part to be curled forced against it by 
the sliding tool at the other end, thus making two bends in one 
operation. 



BENDING AND FORMING DIES 



35 



Seaming Die. — The details of Fig. 54 show two dies for form- 
ing and locking an inside seam on small cans, buckets or other 
round or oval tin bodies. 

The seam of the shell is formed at about 35 degrees to the left 
of the center of the die and is closed on the die shown in front 
elevation. They are similar to horning dies. 



O I S) O^r O 




^"OPERATION 



] [ 




FRONT VIEW OF DIE AND PUNCH 



FRONT VIEW OF DIE AND PUNCH 



Fig. 54. — Forming and locking 



The size of the die and the press depends upon the size of the 
work. The dies shown were built for a bench press with open 
front. The shell before the seam is formed is shown in A. In 
B it is shown with the seam formed. C shows shell ready to be 
closed and D shows it closed. It will be noticed that as the seamed 
shell is formed off center, when put on center the tendency is to 
close it in the right direction. 



CHAPTER II 
PUNCHING, SHEARING AND BLANKING 

While it is difficult to keep all punches and dies in separate 
fields owing to the combinations which are often found in one 
operation, it is thought best to classify them to some extent at 
least. This will, it is hoped, make it more convenient to find the 
desired information without reference to the index. 

Punching Holes in Block Links of Bicycle Chains. — This 
proved a most troublesome job to get started, but was suc- 
cessfully worked out as shown. The fixture was to punch the 
holes in the center blocks of bicycle-chain links. 

The most important problem was to make the punches hold 
up. The chain blocks were %q in. thick and the holes only 
0.161 in. diameter, so the punches were considerably smaller 
in diameter than the thickness of the metal to be punched. The 
press was running 210 r.p.m. and the proprietor would not 
consent to a reduction of speed. Owing to the small size of the 
punches it was feared they would not hold up; but to make sure 
of this, a temporary punch, die and stripper were made, the chain 
blocks laid on the die and punched. 

The punches held up better than expected, but the chain blocks 
were mashed and spread. The next move was to make a tool- 
steel plate %e in. thick with a hole in the center just the shape 
and size of the chain block, in which the chain block was a snug 
driving fit. Guides were made and a stripper on the die to locate 
and hold the plate. A block was driven in the plate and punched; 
driving in the next block drove the punched block out. The opera- 
tion was slow, but quite a number were punched in this manner, 
showing that the punches would cause very little trouble from 
breaking, but would have to be ground quite frequently. The 
pitch and size of the holes were maintained much better in this 
manner than by drilling. It did not require a stripper over the 
blocks but only over the plate, as there was considerably more 
friction between the blocks and the plate than between the blocks 
and the punches. 



PUNCHING, SHEARING AND BLANKING 37 

At this point an interesting and unexpected feature of the job 
turned up. It was intended to ream the holes after they were 
punched, but when this was tried it was found necessary to anneal 
them. The holes had a smooth burnished surface that was so 
hard that a reamer would only stand up for two or three blocks. 
Whether this was due to the thickness of the metal in proportion 
to the size of the hole, or to the metal being so closely confined, 
or to the speed of the machine, no one seemed to know. This 
difficulty was obviated by not reaming the holes at all, as it was 
found that by making the holes in the die only about 0.001 in. 
larger than the punches there would be no breaking out of the 
metal in the punched holes, and the holes were so smooth that 
they could not be improved by the reamer. It was also found 
that the punches, too, became dull quicker than they would 



G4-84-G GGGGGGGGGG 



* 



Fig. 55. — Plate for holding blocks being punched. 

have done if . more clearance had been allowed between the 
punch and die. 

This gave sufficient experience to enable us to make a practical 
fixture for punching these blocks, which was done in the following 
manner: Fig. 55 shows the jig or plate for holding the blocks 
while they were being punched. It was made % in. thick, or 
twice the thickness of the blocks; this was done so that the holes 
a, a 1 , a 2 , etc., could be made a snug driving fit for the blocks in the 
lower half of the hole, while the upper half was made larger so 
the blocks could be dropped into them easily. It was quite 
easy to fill this jig by dropping a block in each hole, and they 
would rest with their top sides about on a level with the upper 
surface of the jig, as shown at a, Fig. 56. 

The holes b, b 1 , b 2 , etc., are pilot holes % in. diameter counter- 
sunk at the top. Fig. 56 is a cross-section on the line t,t of Fig. 
55 and shows the punches, punch-holder, jig and die. A, Fig. 
56, is the punch-holder proper, B is a square block into 
which the punches C are driven — only one punch is shown, the 
other is directly behind it ; this block fits closely in the recess made 



38 



PRACTICAL DIE-MAKING. 



for it in the holder A and is held in place by a clamp and two 
screws in the holes H and H l . 

It was necessary to make this block, because the punches 
needed grinding so often; the block could be taken out, the 
punches ground and the block put back without resetting the 
die. Two or three of these blocks were finally made for each 
machine and the blocks changed when the punches needed grind- 
ing. G and G 1 are the pilots; two pilots were used because it was 
necessary to locate the jig very close, in order to always punch the 




Fig. 56. — Punch and die for chain blocks. 



holes in the center of the blocks. F and F 1 might be called 
pushers, because their purpose was to push the blocks in and out 
of the jig. The stripper is not shown; it was fastened to the 
bolster plate and only extended over the edge of the jigs. D is 
the jig and E the die. 

In using this fixture three jigs were made for each press and 
three persons assigned to each press — two filling the jigs and one 
operating the press. After a jig was filled the operator would 
run it through the press as if it were a strip of steel he was punch- 
ing. At the first stroke the pusher F would push the first block 
from the loose to the tight part of the jig. At the second stroke 



PUNCHING, SHEARING AND BLANKING 



39 



C would punch the first block and F would push the second one 
in. At the third stroke F 1 would push the first block out of the 
jig into a box below, while C and F were working on two other 
blocks. After this a block would drop in the box at each stroke, 
so it took seventeen strokes for fifteen blocks. After the operator 
ran the machine a few days he punched blocks so fast that the 
punches got very hot and would not stand up for more than 15 
minutes at a time. A cold blast of air was tried on the punches, 
but it did no good, so the speed of the machine had to be reduced 
to 160 r.p.m. This did very well, and the punches would quite 




B 
Fig. 57. Fig. 58 

Figs. 57 and 58. — Dies for perforating shells. 

often hold up for five hours. It would probably have been better 
to reduce the speed still more. The results obtained from these 
dies were so satisfactory that six specially built automatic 
drilling machines were discarded. 

Perforating Die for Round Shells. — In Figs. 57 and 58 is shown 
a die for perforating round shells. Attention is called to the 
manner in which the punchings pass from the die. The punch- 
ings follow the opening indicated in the section as open and drop 
down through the bottom of the press. The shell after being 
perforated is shown in the center. 

The shells were formerly perforated in a die which allowed 
the punchings to drop into the shell, but this was bothered by the 
small punchings sticking to the shell, owing to the shell and 



40 PRACTICAL DIE-MAKING 

punchings being oily from the oil used in drawing. After giving 
the new method a trial, it was found advisable to arrange all 
similar perforating dies in this way. 

A Piercing, Blanking and Forming Die. — Fig. 59 shows a 
bath-tub overflow strainer, and Fig. 60 a plan of the die minus 
the stripper plate for making it. Fig. 61 is a cross-section of 
the punch and die. 

The die block A was a piece of Sanderson annealed tool 
steel, 134 X 4^ X 8 in. This block was planed to fit the 
bolster B and then laid out as shown in Fig. 60. The slotted 
part of the die was roughed out by drilling a series of holes within 
the lines laid out. This was done by strapping the blank on a 
faceplate of a dividing head and drilling it by indexing around 
for twelve divisions. The large hole and the clearance hole under 
the piercing dies were then bored in the lathe. 

After this roughing-qut process the blank was heated to 
1600°F. and then packed in lime until cool. This annealing 
was done to relieve any strains in the die block. If this 
practice were followed more in the making of expensive tools, 
there would be fewer cracks in hardening and less distortion. 
After annealing, the blank was ground on top and bottom, and 
bridges left from drilling removed and the holes filed to gage. 
The holes for fastening the gage and stripper plates were then 
drilled and tapped. The die was now ready for hardening. 

This was a task requiring great care and judgment on account 
of the great variation in the thickness of metal. The die was 
heated in a gas muffle to 1725°F., and then quenched in cotton- 
"seed oil. After cooling it was put into an oil tempering furnace 
and heated to 500°F. and then allowed to cool. The blank 
was then ground on both sides and the large hole ground to 
size. 

The next operation was making the punch-holder plate C. 
This was done by clamping the holder against the face of the die 
and the small holes transferred. The round hole in the center 
of the piercing die was drilled and reamed through, using the 
die as a jig. After drilling this hole a plug was fitted in it to keep 
the parts from shifting. The two parts were now. strapped to 
the faceplate of a lathe, the large hole trued up with an indicator 
and the hole for the blanking and forming punch D bored. The 
parts are then separated and the slots for the piercing punches 
E worked out. 



PUNCHING, SHEARING AND BLANKING 



41 




42 PRACTICAL DIE-MAKING 

This method of finishing the punch-holder after the die was 
hardened was to overcome the inaccuracy of the center distances, 
due to the possible shrinkage of the die in hardening. 

The twelve oval punches were made between centers on the 
milling machine. The stock was cut off long enough to allow 
for a driving dog and the cutting off of the center in the end of 
the punch. The flat sides of the punches were milled with a 
spiral cutter, the head being indexed around to the proper angle. 
The rounded sides were milled with half-round formed cutters. 
In this manner the punches were easily duplicated. The pierc- 
ing and blanking punches were hardened on one end only, the 
other being left to allow for riveting on the back side of the 
punch plate. A round, hardened-steel plate F was fitted into the 
punch-holder shank G to back up the piercing punches. 

The blanking and forming part of this die can easily be under- 
stood from the drawing. A pressure ring H was fitted into the 
die and over the forming head /. This ring is supported by 
four hard pins J, bearing on the spring plate K. The pressure 
ring serves two purposes — that of holding the blank while form- 
ing and ejecting it when the punch returns. The pilot L served 
to locate the blank in the center. 

This has proved a very successful tool and is used on a No. 
21 Bliss single-acting blanking press. 

An Adjustable Cropping and Piercing Die. — In a factory whose 
product was principally press work, it was necessary to produce 
a large quantity of metal strips, cropped and pierced in various 
lengths and settings; the average number per setting was about 
5000 pieces. 

The usual method adopted was to crop to length in a power 
press, and pierce to pattern by means of locating jigs, in a 
hand press. This method, it will be seen, entailed considerable 
handling and shop room and as the material used was of light 
gage, varying from % X Y% in. to 1 X 3 {q in., and from 7 in. 
to 28 in. long, it was decided to experiment on the adjustable 
cropping and piercing die here described, capable of performing 
the whole work in one operation. The eventual result was a 
steady output of finished strips at the rate of 700-800 per hour 
at an average of one-tenth the previous cost. 

A special feature is the construction of the punches and dies, 
which effect a considerable saving in money and time. 



PUNCHING, SHEARING AND BLANKING 43 

The general arrangement of this adjustable die is as follows: 
The top tool A, Fig. 62, is of mild steel 2% X 2% X 30 in., 
having six 1-in. tapped holder holes 1J4 m - deep drilled at 
intervals of 2 in. from the center to the right-hand side. This 
allows adjustment to obviate undue side stress on the plunger 
of the press, owing to the cropping operation, which is the 
heaviest, having to be performed at the extreme end of the right 
side of A. A good rule to follow is to mount the top tool holder 
in the hole nearest to one-third the length of the strip to be 
operated upon; thus for the strip K, Fig. 63, the holder would 
be mounted in the hole nearest to 7 in. from the cropping die, 
which is actually the third from the end. 

Owing to the extreme variance in the recesses of press slides, 
it is useless to suggest any particular size for the holder, but it 
is advisable to have the flange at least 2}4 m - diameter to re- 
lieve the side strain falling on the thread. An important 
point is the provision of the holes M, Fig. 62, for the tie rods N, 
which are bolted in turn at the highest point possible on the slide 
of the press and relieve the inclination to spring at the moment 
of compression. 

The female dovetail B, Fig. 62, should be accurately machined, 
and twenty-nine %-in. tapped holes are drilled equidistant from 
end to end and used as necessary in holding the punches, by 
means of square-head setscrews. 

The Bottom Tool and Strippee 

The bottom tool D and the stripper E are illustrated in Fig. 
63. The first is a casting and the second a strip of 2% X %- 
in. black mild steel. A female dovetail is cut to within 2% in. 
of the cropping end and here a square depression 1H X 1^ X ^ 
in. deep is provided for receiving the cropping die and a hole 
sufficiently large to allow the scrap to fall is continued through. 
This is 1}£ X l}?i in. in this case and is rough cored. 

Central to and running the whole length of the dovetail C is 
the channel marked by dotted lines G, which terminate at the 
base in five holes marked H on the plan. This arrangement 
allows a fall for the punchings and, as there is little side pressure, 
does not detract from the strength of the casting D, which is 
fastened to the bed of the press by dogs bearing on the wings J. 
As in the case of the top tool the dovetail should be nicely 



44 



PRACTICAL DIE-MAKING 



Y 



i^ 



! ° 
I O 

r ! o 

W\ ° 

! o 

;! o 

! ° 

•! o 
i 

! ° 

!) O 

! ° 

Si; o 

! o 

JTlTiTv j 

I ° 

! -o 

I ° 

< | o 

| o 

I o 

! ° 

! O 



N ° 



I 



"> 



If 

6" 



£k*>- 



M^i 




L-*_J 1,1* 



If 



Hs 



!— Jo 



h 



I o 



|-~ - o 



- 



O 



«? 



■ 3 



B 



^8 



®. ® 



®^@ 
o 







® © 



e?@ 



n g 

. to 

o 



U^~J 



PUNCHING, SHEARING AND BLANKING 45 

machined and the face and the base planed. Ten holes should 
be drilled at points marked T for holding the various strippers 
and %-in. tapped holes should be drilled in the side, 1 in. apart, 
as shown. The stripper E explains itself and is drilled as re- 
quired. In this case four distance pieces are fastened perma- 
nently at Y and locate the strip shown finished at K. 

The Punch. — -Fig. 62 illustrates the punch and die construc- 
tion, the former being in three distinct parts, namely, the punch 
holder, the punch sleeve and the punch. The holder should be 
case-hardened and nicely fitted to the dovetail B, and as many 
should be provided as may appear necessary, having regard to 
the number of holes to be pierced at one setting. A %§-m. 
tapped hole is drilled half way through the center and taper 
reamed from ^ to J-{q in. completely through. The sleeve is 
of mild steel, and in this illustration is dimensioned for a 34~ m - 
punch. The thread and taper are, however, standard for inter- 
changing. . A three-way slit is cut at the taper end and the taper 
is so proportioned that when the sleeve is tightened completely, 
it forms a strong grip on the punch. 

The punches are merely pieces of drill rod cut off, ground to 
the length required and kept in stock. This material has been 
known to punch over 55,000 holes without fracture. 

The Die 

The die also has three parts, the die holder, the die and the 
setscrews. The holder is of mild steel to fit the dovetail and 
has a recess in the center % in. in diameter by ^{q in. deep 
for the die, with a hole completely through for the scrap to fall 
through. The die is of tool steel hardened and tempered and a 
groove is turned to take the point of the setscrews. A good fit 
in the die is essential and therefore it is advisable to grind to the 
correct diameter after hardening and tempering. An extra die 
holder may be tapped in the center and fitted with a fillister head 
screw, thus forming a stop, as illustrated at S on the plan, Fig. 63. 

This tool is used on a Bliss-Stiles No. 4 press and in adapting 
the idea for general use, the following points should be observed : 

Determine the thickness of the bolster so that when piercing, 
the slide of the press is as high as the screw adjustment will 
allow. 

Fix the apex of the triangle formed by the tie rods N, Fig. 62, 



46 



PRACTICAL DIE-MAKING 



as high on the slide as possible. See that the slide is free from 
side play and thus obviate broken punches. 

Punch Press Shearing Operation. — An order for several thou- 
sand of the pieces shown in Fig. 64, was made from soft steel 
0.020 in. thick drawn up into shells, in two operations, in the 
usual manner. The difficult proposition was to cut off one side 
and part of the end, the cut having to be in a slanting direr 1 ion, 
leaving the edge at the end a part of a circle with a 1^-in. radius. 







Fig. 65. Fig. 

Figs. 64 to 66. — A punch press shear. 



The tools illustrated in Figs. 65 and 66 accomplished the operation 
successfully. 

The lower shear A, Fig. 65, which has a hole through it to facili- 
tate the removal of the shell after the operation, has been per- 
formed, is so mounted in the shoe B that its shearing face stands 
perpendicularly. The clamps C and D are pivoted on the 
extension of the shoe, as shown, and are kept open by means of 
the spring E, to allow the shell to be placed on the shear post A. 
Two pins F,F in the clamps extend into the hole drilled in the shoe 
limiting the amount of opening. The spring buffers G,G are ar- 



PUNCHING, SHEARING AND BLANKING 



47 



ranged to engage with the inner faces of the yoke plate H, which 
is secured to the upper shear I, Fig. 66, and serve to securely 
clamp the shell to be cut, and support it right up to the shearing 
edges of the post A. 

Objections to be pointed out are: First, the difficulty of setting 
the tool up in the press, which might be overcome by arranging 
guide posts and thus making it into a sort of subpress fixture. 
Second, the fact that when shearing post A needs grinding it 
must be thrown away and replaced with a new one, as it cannot 
be ground without losing its necessary dimensions. 

Punch and Die for Two Sizes of Wrenches. — The engraving, 
Fig. 67, shows a punch and die for making wrenches. In this 




© 


» © 




°P D 












o 

v. 


. ° 




© c 


) 





THE PUNCH 



CZ3 



THE DIE 



Fig. 67. — Two wrenches from one die. 



die the punches are so arranged that by running the stock 
through either way a different size wrench is blanked out. The 
size of the body remains the same, but the square is changed. 
In blanking a %6 _m - wrench the stock (10-gage sheet steel) is 
fed through from the right-hand side and held against the stop 
pin on the opposite side. 

In changing for a 3^-in. wrench this stop pin is driven down 
below the surface of the die and the one on the opposite side is 
driven up. The stock is then fed through from the left-hand 
side. No changing of punches is necessary. After the wrenches 
are blanked they are flat-dropped, tumbled, and case-hardened. 



48 PRACTICAL DIE-MAKING 

Shearing Dies for Ball-bearing Cones. — Back in the early- 
days of the safety bicycle, when the selling price of a good 
machine ranged around a hundred and fifty dollars, little at- 
tention was paid to economical production, nor did the real 
squeezing come until the price fell below one hundred. But 
with the price hovering around seventy-five, it became a grand 
scramble for labor-saving devices and short cuts. Stampings 
took the place of machined forgings in some cases, and various 
other changes took place. 

It was during this wholesale digging after short cuts that 
the two dies shown were evolved, and since they are so ex- 
tremely simple they may possibly be of use to someone for 
other classes of work. 

The firm was making a line of cones similar to Fig. 68 and 
these cones were made on an automatic screw machine, from 
round bars of cold-rolled steel. The automatics, turned, tapped 
and cut off the cones, leaving nothing else to be done on them, 
but to cut in the wrench holds, and harden them. 

A few years earlier a milling machine would have been rigged 
up to mill the flat wrench holds on them, but now a punch and 
die was made to shear out these places. Fig. 69 shows the side 
and end views of the die. It was made of a solid block of tool 
steel and set into a cast-iron plate. 

The cones were slipped into the hole in the die, sheared off 
and knocked out by hitting the plunger with one hand. 

In Fig. 70 is seen the shearing punch used. This punch was 
made of one piece of round tool steel and was milled out, after 
which a slight clearance was scraped in by hand. Two sides 
were made alike, so that when one side became dull the punch 
was turned around. 

At first a bevel was ground on the cutting edges, but this was 
soon abandoned and the punches ground perfectly flat on the 
bottom. This gave just as good results in the work and the 
edges did not chip off as much. 

Nothing was used to hold the cones except the friction in the 
hole, but they had no tendency to turn and break the punch, 
as was at first feared. 

A set of punches and dies was made for each size of these 
cones and these were used for three or four years. 

Another class of cones made by this firm were also made from 
round bars of cold-rolled steel on automatics, but owing to the 



PUNCHING, SHEARING AND BLANKING 



49 



shape, they had to be sheared for the wrench holds in another 
style of die. 

The shape of this cone is shown by Fig. 71 and Fig. 72. It 
was made from a flat piece of steel which was slotted as shown. 
A flat spring stop, with a big end, was used to prevent the cones 
from being shoved in too far. 

The cones were simply slipped into the slot in the die, with 
the thin flange of the head on top, and then shoved down through 




Fig. 69. 



\\ ft 



Fig. 70. 



/ 


/ 


\ 








% 




n ) ; 


oo) 






y 





Fig. 72. 





Fig. 73. 
Figs. 68 to 73. — Shearing cones for ball bearings. 



with the punch shown by Fig. 73, a hole in the bed plate letting 
the cones drop down into a box. 

As will be readily seen, the punches and dies were very easily 
made, scarcely any hand work being needed and very little 
steel used. 

So smooth was the work of these tools when kept sharp, that 
except for the few that were nickel-plated, none of the cones 
were polished, but were simply case-hardened, ground a little 
on the bevel face, and sent out. 

Punch and Die for Ratchets. — At A, Fig. 74, is shown a small 
ratchet, *?£ in. in diameter, made on automatic screw machines. 

4 



50 



PRACTICAL DIE-MAKING 



The teeth were formerly milled on an automatic gear-cutting 
machine. Hobbing was tried without increasing production, 
so shearing the teeth with a punch and die was suggested. To 
do this with as few motions and as handily as possible the punch 
and die shown in the illustration was designed. 





I I l , ! l ! .l 1 ) 



I 




' 




















y 




















1- 




II 




-- 






1 1 


!i • 

IL. L . 


Nil 







c 



ID 



Fig. 74. — For punching ratchets. 



The object in having the punch and die reversed is to make it 
easier to feed and locate the work. 

The ratchets are placed on the punch with their stems in 
the hole. The punch forces them far enough through the 
die to require but little force to push them the rest of the way, 
thus avoiding upsetting the ends. The next piece forces the 
one ahead of it against the curved surface B, causing it to tip 



PUNCHING, SHEARING AND BLANKING 51 

over onto the incline C. The jar of the press keeps them mov- 
ing out of the way down the inclines C and D. 

The hole in the lower member should not fit the stems too 
closely and may be countersunk a little to help in placing the 
ratchets. To avoid confusion the screws and dowels for hold- 
ing the two upper blocks to the punch holder are not shown. 

This punch and die did very satisfactory work and increased 
the production on this operation several hundred per cent. 

Punch and Die with Automatic Spacing Device. — The ac- 
companying illustrations show a semi-automatic punch and die 
designed for accuracy on work of a somewhat peculiar nature. 

Referring to Fig. 75, it will be seen that the work produced 
consists of evenly spaced holes in a narrow strip of metal, this 




DODOD0D0DDD 



Fig. 75. — Punching evenly spaced slots. 

was 18-gage, or 0.05-in. cold-rolled sheet, and the purpose of 
the holes was to form the adjusting supports for shelving which 
could be spaced to suit convenience. 

As a considerable quantity of these strips was required from 
time to time and it was necessary that the spacing on all dif- 
ferent lots should be exact, not only from one hole to the next, 
but between any two holes, the ordinary type of stop or gage 
pin was unsatisfactory. 

For one reason it would wear slightly and a couple of thou- 
sandths on the pin meant nearly y% in. on the full length of the 
strip, and then also it was practically impossible to fit two pins 
exactly alike, in case one was broken off or a new die made. 
These difficulties were entirely overcome in the manner shown. 

Referring to the punch and die, Fig. 76, it will be found that 
there is no gage pin but instead, a spacing bar, with the 'required 
spacings permanently established and by the nature of the 
plunger A, Fig. 75, each stroke of the press indexes the work 
forward the required amount. 



52 



PRACTICAL DIE-MAKING 



The action and operation are as follows: to start, the in- 
dex bar B is drawn to the right until the stock support C strikes 
the die block D when the work is pushed against it as a stop and 
the first hole punched, the dog being prevented from operating 
on this first stroke by a wire hook held in the hand, which pulls 
back the dog by means of the knob E. The work is now fed 
forward by hand and hooked over the pin F and the latch G 
swung around to prevent its springing off when the second hole is 
punched with the rod held out of engagement as on the first 
stroke. For the third and remaining strokes, the dog is allowed 
to operate and the foot kept on the treadle until the piece is 
finished, each stroke spacing and punching its own hole complete. 

As a difference of a few thousandths between any two holes 
was in no ways vital, no more accurate locating device than the 



rcb 





Fig. 76. — The automatic spacing device. 



forward movement of the dog was necessary, it being only re- 
quired to avoid the cumulative error introduced by a long or 
short gage pin. This the device shown accomplished, besides 
making a considerable saving on the punching time, as evidenced 
by the piece-work rates. It also reduced spoiled work to almost 
nothing. 

A Multiple Hand Punch. — Fig. 77 shows a hand punch for 
piercing three small holes at once in a thin brass shell. The 
plan gives a clear idea of the principle, which leaves little to ex- 
plain. The cam plate is made of mild steel, the body of gray 
iron and the punch holders are of round cold-rolled stock. 

The bushing or die in the center is forced into the cast-iron 
body a short distance, and further secured with a setscrew (not 
shown, nor, for the sake of clearness, are the holding-down lugs 
shown on the elevation). This bushing is hardened and ground 
and the capscrews are case-hardened. The small holes going 
through the punch holders permit broken punches to be driven 
out. 



PUNCHING, SHEARING AND BLANKING 



53 



Punching Tool for a Fiber Washer. — This tool was designed 
to avoid a second handling of the small fiber washer shown in 
Fig. 78. The general construction of the tool can be readily- 
understood from Fig. 79. The bolster and cutting die A, the 
forming die B, the piercing die, the guide C for the punch D, 
which also acts as a stripper for the punch holder E, were all 
made of cast steel. The punch holder was made of mild steel. 




Fig. 77. — Multiple hand punch. 



The piercing punch F was fitted with the strong square-section 
springs G and H, the latter being rather the weaker. 

The action of the tool was as follows: The punch D engaged 
the material and formed it to shape; owing to the relative 
strength of the springs G and H, the spring H gave way and 
allowed the punch F to pierce the material, whereupon the punch 
D blanked it out. The tool was very successful and made a good 
job of the washer. 



54 



PRACTICAL DIE-MAKIXd 



Compound Die for Celluloid. — The compound die shown in 
Fig. 80 is intended for piercing and blanking celluloid, which is 
used extensively in the manufacture of eyeglasses. The work is 
left in the strip from which it is easily and quickly removed. The 
pressure required to force the blank back into the celluloid is 
small as compared with that used for metal, hence the compact 
construction of the die. 

The tool consists of a shank A, to which is screwed the piercing- 
punch holder B. A die C is in turn screwed to the holder B, 
which is recessed to admit of the knockout D sliding therein. 




THE WASHER 




the punch and die 
Fig. 78. Fig. 79. 

Figs. 78 and 79. — Tools for punching fiber washer. 

This knockout is operated by the spring I through the pin H. 
The punch, which is placed at the bottom or in the regular die 
bed, is made as illustrated at E and has a stripper K held against 
the studs G by the springs F. The pins L, which are hardened 
and ground, are for the purpose of setting the tool in the press 
and also to prevent shearing of the punch. When the piercing 
punches break, they may be easily replaced by heading over a 
piece of drill rod, hardening and replacing the defective one. 

On such work as these tools were designed for, they last almost 
indefinitely. 

Hot Punching of Forgings. — A somewhat radical develop- 
ment in the field of drop forging has been made and tested out 



PUNCHING, SHEARING AND BLANKING 55 

by the Consolidated Press Tool Co., Hastings, Mich. This 
shows what has been accomplished in the way of hot-punching 
drop-forgings, in some cases eliminating machine work. The 
operation might almost be called a secondary forging. 

A plant of this kind installed in a large automobile works shows 
some interesting results. The machines used are large double- 
acting crank presses designed especially for this work; the 
larger press weighs 50,000 lb. and stands about 13 ft. high. 



*-A 



■^ 






THE PUNCH 




Fig. 80. — Die for punching celluloid. 



This has a capacity of punching a hole 4^ to 5 in. in diameter in 
stock 234 to 23^2 in. thick when heated to 1400°F. The furnaces 
are placed convenient to the presses to facilitate handling the 
work. These open at both ends, the pieces being put in at the 
back and worked toward the front by the helper, reaching the 
proper temperature when at this end. 

Figs. 81 and 82 show work both before and after punching. 
The first is a connecting-rod and the second a support for the 



56 



PR A CTICAL DIE-MA KING 



differential bearing, these being selected as good examples of the 
new process. 

Punching Two Holes at Once 

After the connecting-rods have been forged, as the one at A 
in Fig. 81, they are reheated and placed in the holding dies shown 




Fig. 82. — Bearing support and punches. 

in Fig. 83. These dies are duplicates of the forging dies and can 
be made adjustable for length. The upper die is held in the 



PUNCHING, SHEARING AND BLANKING 



57 



outer slide, which comes down on the work before the inner 
slide descends. This inner, or punching, slide then comes down, 
punches the holes, and returns; the outer slide lifts, the work is 
taken out, and a fresh piece put in. But while the operation 
takes little time, there were many interesting problems to work 
out to secure complete success. 

The small hole is punched 21 /z2 m - m diameter from the solid 
through a section 1 in. thick, while at the large end the punched 
hole is 1 5 %4 in. in diameter through a section 1^ in. thick, 
although the punch takes out only the draft on the sides of the 
hole. The two punchings may be seen at B and C in Fig. 81. 
The large hole is not machined, except to mill cross-grooves for 




Fig. 83. — Dies for hot punching. 

anchoring the babbitt, while the small hole leaves 3^2 m - to be 
removed, making it % in. in finished diameter. 

In a similar manner the larger hole is punched in the differential 
bearing support, this hole being punched 3%e in. and afterward 
bored to 3.67 in. The amount of machine work saved can be 
seen from the size of the piece punched out, as shown at A in 
Fig. 82, although this does not show the metal in the draft at the 
sides of the hole. 

Perhaps the most interesting features of the process are the 
punches and the way they are handled. These are shown at D 
and E, Fig. 81, and at B and D, Fig. 82. The smaller punch in 
Fig. 81, 21 / / z2 in. in diameter, is of high-speed steel; the others are 



58 PRACTICAL DIE-MAKING 

of cast iron, which is employed for all punches over 1% in. in 
diameter. 

White cast iron is used. The punches are turned, hardened 
in cyanide, and ground straight except for the beveled ends. 
Both the steel and the iron punches are beveled in the same way, 
and both last from 200 to 500 holes, a wear of ~%± in. being 
allowed before discarding. 

In operation, the helper places a heated piece in the dies, the 
operator having already put a punch in the holders. Moving 
a lever trips the press, and the outer slide with the upper half of 
the holding die comes down over the work. Then suitable arms 
push the punches under the inner slide, which forces them through 
the hot forging, allowing them and the punching to drop in a pan 
of water below. The punches are recovered by the operator 
with a pair of tongs. 

Fig. 83 shows how the punches are driven through the work by 
the plunger; how the plungers, or drivers, are held; and the way 
in which the die is adjusted for center distance between the two 
holes. The large hole is shown at the left and the small, or upper, 
end at the right. 

Some of the advantages of this process are apparent. The cost 
of heating is eliminated because this is part of the heat-treat- 
ment and would be done in any case. The pieces are heated 200° 
hotter than needed for the punching, or 1600°, in order to fit into 
the heat-treating specified. The forgings are of manganese 
steel. 

The two holes are punched as quickly as one, the number being 
limited by the capacity of the machine. One machine handles 
an average of 100 connecting-rods per hour. Add to this a 
charge of 20c. per 100 holes for tool cost, setting-up and repairs, 
and the economy of the method becomes apparent. 

This, however, is not the only economy. This being in reality 
a reforging operation, it saves practically all forgings which may 
have come out of the first dies a trifle long or short; the holding 
dies reshape them wherever necessary. Further, the cone-ended 
punches force the metal into the dies, compressing it and making 
it more dense around the holes. 

Cutting Two Blanks at Each Revolution. — The accompanying 
illustration, Fig. 84, shows a blanking die which was recently 
made, to cut out two blanks of 16-gage material at one revolu- 
tion of the press, and it worked to perfection. This shows the 



PUNCHING, SHEARING AND BLANKING 



59 



die with the stripper plate removed. The heavy lines show 
the openings made in the die for punches A, B,B and C,C. D 
is a stop made of machine steel, case-hardened. E,E are gages 
for the stock to slide between under the stripper plate. F,F,F, 
in dotted lines, represents the first blank as it is operated on 
until it slides off the die through the gap H, between stop D 
and gage E. G in dotted lines, represents the second blank until 
it is blanked through the opening A in the die. Opening A in 
the die is made a little longer than the blank G, so as to overlap 
the ends, and let the punch that fits into opening A cut only on 
the sides. Punches B,B should be ground along the line of the 




Fig. 84. — Double blanking die. 



gages so that their backs can enter the die before their fronts cut 
the stock. This die works best in an inclined press, as then 
blank F can slide off the die. 

To operate, insert the stock between the gages far enough 
for punches B,B to cut a half moon out of each edge and perfor- 
ate the small hole CC with the first stroke of the press. For 
the second stroke of the press advance the stock until the per- 
forated hole in blank G comes in line with the pilot that fits into 
opening A. This will cut blank G through the die and let the 
scrap from the end of the strip slide off the die through gap H. 
Now advance the stock until it strikes the stop D, and with the 



60 



PRACTICAL DIE-MA KINC / 



next stroke of the press you will cut two blanks, one going through 
the die and the other sliding off through gap H. 

Piercing, Curling and Cutting-off Die. — The steel plate 
shown at A, Fig. 85, is part of a typewriter. The hooks in these 
plates were formerly made as shown at B and C, a slow and 
costly method. Now this punch and die are used which are of 
the pillar-press type. The shearing and curling punches are 
made as shown at D and fitted into a punch plate; they can be 
removed for grinding. 




^^ 



5 Section G 

through Hook 

of-Plate 

A 



Fig. 85. — Piercing and curling a typewriter plate. 

A conventional stripper plate is screwed to the die and a 
flat bar with an adjustable stop is screwed to the die-holder. 
Simplicity and ease in curling the hooks is the feature of this 
tool. 

The operation of forming the hooks is clearly shown, the 
beveled side of the punch curls the hook. The secret of suc- 
cessfully forming the hooks lies in having the proper angle X 
on the punches; this angle is determined by experiment, it varies 
with different grades of stock. 



PUNCHING, SHEARING AND BLANKING 



61 



By having the proper angle on the punches, it was found that 
the hook can be completely curled up if desired, as shown at 
E. In operating this tool the stock is fed to the cutting-off 
edge of- the die and the holes and hooks are pierced and formed, 
stripped against the stripper plate, moved along again to the 
stop and cut off and so on. A complete plate is produced at 
every stroke of the press. 

The flat F on the end of the punch will produce hooks as 
shown at G. This method has greatly increased production 
and reduced the piecework price. 







-i=5 










( 

I 

[r 

¥ 


ID c - 
> 


A 














Rubber Pticf — •' 

THE BLANKING PUNCH 




^7 



Fig. 



-Blanking tools for staples. 



Press Tools for Tin Staples. — The illustrations, Figs. 86 and 
87, show a cheap set of press tools for staples. These have re- 
placed more costly tools, make no scrap and have cut the cost of 
material in half. 

The stock used with the old tools was tinned strip steel %X 
0.013 in., which was brought from the continent. The strip 
tin was fed to the die by a roll feed on the front of the press, 
running at 140 r.p.m., one staple being blanked at each stroke. 
At the back of the press was a series of rolls that bent the staples 
at right angles as the strip fed through the blanking tools. They 
were then cut to the required length, 3 in. for 25 staples, 6 in. for 
50 staples, and the like. 

The new tools, as shown, are more simple, and although 



62 



PRACTICAL DIE-MAKING 



there are two separate operations, blanking and bending, the 
output is greater, as 25 staples are blanked with each stroke of 
the press and 25 are bent at right angles at each stroke. The 
new tools are made to fit either the power press or the screw 
press; they are shown here in the screw press.' 

Fig. 86 shows the blanking tools, where A is the steel die, B 
the stripper, C the guide for the stock which also keeps the 
blanking punch up to its work, D a stop which is pushed in for 
the first blank and when released is held back by the spring E. 
The teeth on the stop D are used as a guide and stop for the re- 
mainder of the blanking. After each stroke of the press the 




I <p y <$> I" 




Fig. 87.— The bending die. 



tin is pulled toward the operator about % in. and pushed along 
till the teeth on the stop D locate the stock in the right position, 
the raised piece F keeping the tin in line with the stop D, while 
the blanked strip travels underneath the stop. 

In the front elevation and part section there can be seen the 
pressure pad and stripper, which require little explanation. 

A milling cutter was made to the required dimensions to cut 
the die, punch and stripper. This made the job of tool making 
comparatively easy. The bending die is shown in Fig. 87. 
This is set at an angle to the base to make it handy for the opera- 
tor to feed the strip along. The guide pieces G,G are screwed to 
the forming die and when the strip of tin is first fed up, only two 
or three staples are bent, as this helps keep them central. After 
this twenty-five staples are bent at each stroke of the press. The 



PUNCHING, SHEARING AND BLANKING 



63 



former H is made quite long, as this helps to support the staples 
and also acts as a guide. 

The punch is shown in section and end view to illustrate how 
the staples are prevented from leaving the bending die with the 
punch. ' 

The sheet of tin is turned upside down after each strip is 
cut off. This procedure keeps all the burr on one side, other- 




Hand press used for making staples. 



wise there would be a burr on the top of one side and a burr on 
the bottom of the other side of each strip of staples. 

The first strip of staples cut from the tin plate has to be fed 
through a second time, as there is only one side perforated on the 
first strip. From one sheet of tin, 24 X 25 in., we get 32 strips 
with 200 staples on each, making a total of 6400 staples (or paper 
fasteners). This is double the output by the old method. 

American tool makers will, no doubt, smile when they see 
the illustration of the screw press, Fig. 88. There are fifty of 



64 PRACTICAL DIE-MAKING 

these to one power press in the vicinity of Wolverhampton, Eng- 
land, where these tools were used. They do seem prehistoric, 
but a girl doesn't mind blanking brass % X 2 X 3-in. stock 
on them. 

A Blanking Die and Forming Tool for a Clip. — The illustra- 
tions, Figs. 89, 90 and 91, show a blanking die and forming tool 
for a small clip. The forming tool is quite different from the 
usual. 

Fig. 89 shows two views of the clip, one as the blank comes 
from the blanking die and the other as it is formed up ready 
for use. 

This clip is used on the keyboards of typesetting and casting 
machines. They are made fi;om half-spring steel and being 
used in large quantities must be made cheaply. 

The punch and die, Fig. 90, is a simple follow die. First the 
hole is punched, then the stock is moved along. A finished 
blank and the hole for another are made with the next and sub- 
sequent strokes. A boy can punch about 8000 per day. 

The former, Fig. 91, consists of a block of steel A, with eight 
slots or grooves B spaced 45 degrees apart in the center. A 
plunger C works through the center of the block with two collars 
D,E turned on it about }i in. apart. You will see at Fig. 91 
that the eight pawls F work in the slots and are centered in the 
block with the tail of each working in the groove in the plunger. 

The plunger has a pilot G on the top end which fits the hole 
in the blank. The blank is dropped in a form which sets the 
wings in their proper place. The punch H is just the shape of 
the finished clip. The punch H descends and holds the blank 
firmly on the plunger C and pushes it and the plunger on down 
into the die. As the plunger is forced down it draws the tails 
of the pawls F down with it. As they are centered at one side, 
the tops of the pawls are forced in and when .the press is at the 
bottom of its stroke the pawls are forced up tight against the 
punch. 

As the press ascends the spring I on the bottom of the plunger 
forces it up, opens the pawls and frees the formed blank which 
sticks to the punch. A stripper set at the proper height strips 
the blank nearly off the punch. When the operator is putting 
another blank in he gives the formed piece a slight knock which 
removes it from the punch. It falls in a trough and is carried 
to a box under the press. A boy can easily form 5000 per day 



PUNCHING, SHEARING AND BLANKING 



65 



on an ordinary single-acting press. When assembling the pawls 
in the base A, all the pins upon which they are fulcrumed except 




the last can be driven from the outside. The last pin is dropped 
in from the top, the block A being recessed for that purpose. A 
small cap fits on top of the pin and is held in place by two screws. 



66 



PRACTICAL DIE-MAKING 



Thickness of Blanks. — In the design of dies for press work, 
the thickness of the stock often plays a more important part than 
appears at first glance. For instance, the blank shown at A> 
Fig. 92, could readily be made in the follow die B providing the 
metal were thin enough. This die pierces the two holes C at the 
first stroke and at the second stroke, the whole blank A is punched. 
With heavy metal, say % m - thick, the tongue D might be found 
rather weak and liable to break. 

To avoid any chance of trouble and without adding to the 
number of stations on the follow die, it should be made as shown 
at E. At the first stroke in this die, the two holes C are pierced 
and also the opening, which in the die B is cut by the tongue 
D. In the second stroke the blank is cut by the die G which has 




Blank 

Fig. 92. — Effect of thickness of stock. 



no delicate members liable to fracture. The punch and die for 
F pierce a hole }{q in. longer than shown on the blank A, which 
assures their being blanked with an open end. 

Die for Can Top and Bottom. — A die and punch for making a 
3%-in. seal top and a 2-in. bottom for tin cans is shown in Fig. 
93. This die was planned to work without springs. At A is a 
knockout pin, the shoulders at B and C, respectively, doing the 
work. The washer B, working against four pins D, which in 
turn bear against the ring E, ejects the product from the punch. 
The pad C ejects the bottom from the punch. 

The four pins in the die bear against a spring rubber, which 
holds the edges of the product smooth and also ejects it from 
the die. The product F is placed into an edging die and the edge 
at G is turned down. This seal top is used on paint and molasses 



PUNCHING, SHEARING AND BLANKING 



67 



cans generally, and admits a cover which is held by friction. The 
product H is the bottom of the can. 

Tools for Cutting-off Angle Iron. — Dies for cutting off small 
angles vary widely in design and while it is not easy to say which 




Fig. 93. — Dies for tin cans. 



is the best type, the one shown will be found useful in many 
places. 

In Fig. 94 is shown a simple, inexpensive tool which is satis- 
factory for certain angles and purposes. This has a 90-degree 
punch and die block. The punch is made solid, and the die is 




n 






vzzzzzm 

3 



Fig. 94. — Dies for cutting-off small angles. 

one piece of tool steel set into a cast-iron shoe. For light angles 
with sharp inside corners, as shown at A, this style of cutting- 
off tool answers very well, especially if it does not matter if one 
end of the piece cut off should be distorted somewhat. The tool 



68 



PRACTICAL DIE-MAKING 



is sharpened by grinding the adjacent faces of the die and punch; 
no back taper is required. 

For angles having fillets in the inside this type does not 
answer, except for rough work, for the reason that at least one end 
of the piece cut off will have its shape destroyed, as illustrated 
at B and C. This will be the end which is not supported on the 
outside by the die, the sharp end of the punch striking the fillet 
and forcing it down before the outer corners begin to cut off. 
This will invariably happen in a die like Fig. 94, and can be 
only partially overcome by rounding the end of the punch to 
conform to the fillet. 

To avoid this, a die, as shown in Fig. 95, must be used. This, 
it will be noted, supports the stock under both ends cut. The 
cutting blade is set between the built-up 90-degree pieces and 
cuts off; the deformed portion is punched off as scrap. It is not 
necessary to build such an elaborate tool as that shown in Fig. 




Fig. 95. — For cutting square edges. 



95, so long as the principle remains the same, but the one shown 
is a remarkably successful tool of the type. 

The punch of this die is not made to conform exactly to the 
shape of the die, nor to the inside of the angle, for the reason that 
by giving it a shear in the manner shown, it cuts much easier and 
produces a cleaner and more nearly square end on the stock. 
The punch in this particular die was made of ^32-in. thick tool 
steel, ground flat on both sides, hardened and drawn to a dark 
yellow. The cutting sections of the die were of high-speed steel, 
in four parts as shown, which, when dull, could be easily removed 
and ground on the ends. These are set up against a spacer (not 
shown), which allowed the required clearance between punch and 
die, and located the die sections in relation to the punch. These 
dies were ground with 1- or 2-degree back taper. 



PUNCHING, SHEARING AND BLANKING 69 

The guide posts were added largely to reduce setting-up time, 
as well as to insure correct positioning of the punch and die in all 
set-ups. They are not necessary to the proper working of the 
die. 

Particular attention is called to the shape of the punch, the 
flat nose, and the edges undercut 5 to 10 degrees from 90 degrees. 
The shape was the result of considerable experimenting to reduce 
the stress of cutting and increase production between grindings. 

The die, in Fig. 95, will cut perfect pieces without distortion, 
% in. long from ~% in. thick filleted angles. The tool shown 
in Fig. 94 on pieces of that length would produce only mis-shaped 
slugs. 



CHAPTER III 
DRAWING SHEET METAL INTO VARIOUS SHAPES 

This is another department of press work which has made great 
advances in a comparatively short time. Cold sheets are now 
drawn and shaped almost at will, into forms which was considered 
impossible but a few years ago, the marvel being that cold metal 
will withstand such stresses without tearing. This is allowing 
the use of sheet metal for many parts which were formerly made 
of castings and machined in various ways. Examples of this 
class of work will be shown in this section. 

Drawing a Difficult Shell in a Single-acting Press. — This 
shows a drawing die, with some novel features. Fig. 96 shows 
the five operations required on a single-acting press to produce 
the finished shell shown in Fig. 97. 

Operation 1 shows the blanking and drawing die which knocks 
the shells out with a kicker that passes through the back of the 
press and rests on the top of the stripper. The cross-section 
and the punch in position shows the little knock-off pin which 
disappears during the operation and which pushes the shell away 
from the stripper to which it is held by suction. An enlarged 
view of the pin is shown at A. 

The punch has a thread cut on it to screw into a plate }4 in- 
thick. This plate bolts to the ram of the press and takes all the 
pull and strain from the setscrew. The blank from this die 
is shown at C. 

The second-operation die is shown in part cross-section, and is 
held in a cast-iron shoe, not shown. A cap bored to take the 
shell C, is threaded and screwed into the shoe. It locates the 
die and holds it. It bears on the 45-degree angle X of the die. 
The draw from this operation is shown at D. This punch also 
screws into the same plate as the previous punch. 

In operation 3 the punch only is partly shown, but it and the 
die are made in the same manner as the previous punch. The 
punch used in this operation is chamfered to give the shell a 
start in the die for the fourth operation. The shell from the 

70 



DRAWING SHEET METAL 



71 



third operation is shown at E, and F is a bottom view of it. 
The fourth operation produces the shell marked G, and H is 
a bottom view of it. The reason of the chamfer is plain as the 
corners on the shell are required to come as sharp as possible, 
and if this had not been done in the third operation, the fourth 
would have made a bad mark about 34 in. up on the shell, which 
would have required a lot of polishing to get out. 




^ 






mr 







i i 










G 


| Shell | 



fUUCU JTUUCU 

3rd Operation 4th Operation 5tb Operation 

Fig. 96. — The five operations required. 

The fifth and final operation is now to be done. The punch 
is made to the exact size and shape (shown reduced in size in 
operation 5, Fig. 96). The die is shown large in Fig. 97 in order 
to make it clear. This was first made to suit the punch but the 
recesses I in the steel tore and scratched badly. The die was 
then slotted out at J, one face of each slot coming out at a sharp 



72 



PRACTICAL DIE-MAKING 



point in the die. This slot was made about ^{q in. wide. A pair 
of rollers was then made and finished out the part of the die 
marked K. 

The edges of the rollers were slightly rounded at L to avoid 
breaking and to make / the shape required. Holes were drilled 
at right angles to the slots for pins for the rollers to turn on, and 
in a position to bring the edges of each roller a trifle below the 
edge of the die. When the shell from the fourth operation was 






— /° ^~s° 


'crz 


j(fe^i(|idj:::D x 




5th Operation Di? 

Fig. 97. — The last die and the finished shell. 



placed in the die it started to draw the body first, and as soon as 
that started it struck the rollers, which rolled in the recesses. 
This left the recesses as smooth as the body of the shell, and it 
required very little buffing to finish them. 

These operations were all done in a single acting press. The 
finished shell is shown at M; it is \ X Y\§ in. long by 134 m - one 
way and % in. the other. It is made of sheet steel 0.045 in. 
thick. 

Forming Rivets in Soft Sheet Steel Parts. — It is easy to as- 
semble work that has rivets struck up in soft steel stock far enough 



DRAWING SHEET METAL 



73 



to allow the riveting of small parts of thin gage, such as flat 
springs, etc. This method of handling work is used extensively 
in manufacturing sewing machine attachments and will be found 
accurate and a labor saver. 

An example of this work is shown at A, Fig. 98. The die B 
and punch D are made in the following manner. Drill and ream 
the die to the outside size of the rivets. Transfer the holes in 
the die to the templet C, made of steel, and counterbore the holes 






Fig. 98. — Forming rivets in soft steel. 

in it for the hollow mill E. Clamp the templet C on the punch 
D to guide the hollow mill E for forming the tits on the punch, 
remove the stock from around the tits that are formed and the 
tools are ready to harden. 

The same die will answer to punch the holes but it is better 
to have two dies, gages being screwed on the die to locate the 
work. 

Piercing Thick Stock. — Two interesting press jobs are shown 
in Fig. 99. At A and B are shown two brass watch plates. The 
original blank was 0.095 in. thick; all the holes in it were pierced 
in a subpress die at one stroke. The smallest holes are ap- 
proximately 0.037 in. in diameter, so that the stock is almost 



74 PRACTICAL DIE-MAKING 

three diameters in thickness. Carbon-steel punches were at 
first used, but these would not stand up for many pieces. 
High-speed steel drill rod was then tried and no further trouble 
was encountered. 

The watch plates as originally blanked out were not flat, and 
several methods were tried without any reasonable degree of 
success. It was eventually decided to try shaving them. A die 
with guides was made so that 0.003 in. could be shaved off each 
side, the pierced plate being pushed edgewise through it. The 
plates thus treated came out within 0.0003 in. of flat and were 




Fig. 99. — Piercing thick watch plates. 

very satisfactory. Beyond throwing up a slight burr on the 
holes, which had to be burred in any case, there was no distortion. 
One of the shavings is shown at C curled up just as it came from 
the shaving die. 

Drawing Curved Shell. — The bending of tubes, especially if 
they are thin, is always a bothersome job. At E is shown a brass 
tube or shell about }4 in. outside diameter with a very thin wall 
and closed end. A few of these were wanted for an experimental 
job. Instead of making a special set of drawing tools, to draw 
up the shells, and a set of bending tools to curve them, the whole 



DRAWING SHEET METAL 



75 



j ob of drawing and bending was done in two operations with very- 
simple make-shift tools. 

There were on hand plenty of shallow cup-shaped blanks which 
were suitable. An angle plate A, Fig. 100, was bolted to the press 
table B. Attached to A was the die holder C with the wide- 
mouthed die D. Mounted on a pivot E in A was an arm F, which 
carried a curved drawing punch G. A link H connected F to the 
press ram I. A cup-shaped blank K was inserted as shown, the 
press tripped and a curved shell was drawn as shown. A 
second drawing with a smaller punch and die brought it to the 
required size. The punch was made as follows: 




Fig. 100. — Drawing a curved shell. 



A piece of drill rod of the correct diameter but considerably 
longer than required was heated, wound around a mandrel of 
suitable size, a piece cut from it, one end rounded off and the 
other fitted to the lever F. 

Blanking and Drawing Shells at One Stroke of a Single-acting 
Power Press. — The accompanying illustrations show a method 
used successfully by a large concern for the rapid production of 
shells similar to Fig. 101 in a single-acting power press. Re- 
ferring to the sketch, A in Fig. 102, represents the frame of a 
regular power press, while B represents the plunger or slide 
with up-and-down movement; C is a solid tool-steel combination 
blanking and forming die, the recess in the center being used for 
drawing the cup over tool-steel post D. 

The cutting die E is placed and located by setscrews and 
dowels in cast-iron die holder F, which in turn is held to the bolster 



76 



PRACTICAL DIE-MAKING 



plate of the press by studs G and H. K is a stripper to push the 
cup from the vertical post after the forming operation is com- 
pleted. The portion of part K, which is marked K-l, is in the 
form of a horseshoe, while portion marked K-2 is a handle. Part 
K-2 is often connected to the plunger of the press with a bell- 
crank lever motion, thereby allowing the caps to be automatically 
knocked off on the up-stroke of the press. 

In addition to the above these tools are provided with a stripper 
for use in connection with the sheet metal as it is fed in from the 
reel. This allows the use of an automatic friction or ratchet 
roll feed, thereby allowing the operator to take care of more than 
one machine. 




Fig. 102. 
Figs. 101 and 102. — Blanking and drawing shells at one stroke. 



The size of the shells manufactured mostly with this equip- 
ment vary from 0.010 to 0.050 in. in thickness; from }i in. to 
% in. in depth and from 34 in. to X}/^ in. in diameter respectively. 
Each shell included in the sizes cited above is done at one stroke 
of the press either from sheet steel, silver, gold, copper, or brass. 
In making the drawing longer an allowance of about 0.003 in. 
should be made for clearance between the stock and the forming 
punch and die. A fine hole should also be left running through 
the center of drawing post D in order to prevent any air pressure 
occurring during the formations of the cap. The other parts are 
extremely simple to make and it is feasible to perform the work 
either in an inclinable or upright press. 



DRAWING SHEET METAL INTO SHAPES 



77 



The output of a press with automatic feed on the smaller sizes 
varies from 110 to 140 per minute, while the output on a machine 
fed by hand ranges from 50 to 90 per minute. 

Press Tools for Oval Flasks. — As every tool maker knows, it 
is easy to draw thin round work even, but with ovals, such as 
the outer casings of drinking flasks, there is considerable difficulty 
to those not familiar with the work. The chief trouble is when 
the first draw is started from a round blank, as it causes an 
uneven thickness of metal, which forms corrugations on each 
side, so the blank must be oval as shown in Fig. 103, when all 
trouble will be eliminated. 




Section of Die 

Fig. 104. 
Figs. 103 to 105. 



Section of Die 
Fig. 105. 
-Tools for an oval flask. 



The first drawing tools, that is, a combination of blanking 
and drawing at one operation, are shown in Fig. 104. The 
second and final operation is shown in Fig. 105, which reduces 
the diameter }■£ in. all round; it will be noticed that the punch 
for this operation carries a sleeve; this is necessary to iron the 
wrinkles out of the sides, as the metal is only about 0.02 in. 
thick. After the shells are drawn they are trimmed on a lathe 
which cuts the edges evenly. 

The necessity for polishing the tools to a glass-like surface 



78 



PRACTICAL DIE-MAKING 



should be emphasized, as the least scratch will show. In fact, 
it is a good plan to burnish them with a hard steel burnisher, 
when they may be used for standard silver or german silver 
(if of good quality), and the finished work will be found first- 
class. 







& \f % 


N 


\ 1 


1 



U— i%--A c 

B 
Fig. 106. — Pressed steel pulley. 



|* 3'^Diam.—A 



D 



One-piece Pressed Steel Pulley. — A one-piece pressed steel 
pulley can be produced by what is known as the inside out 
method, can be made with the least number of operations and 
without annealing. The four operations required are shown 
consecutively in Fig. 106. 






Xh 






Fig. 107. — First operation — die and punch. 



The first operation, A, Fig. 106, is developed from a blank of 
cold rolled steel, 0.095 in. thick and is produced in a single- 
acting press with the combination blanking and drawing die 
and punch shown in Fig. 107. The 12 X 6-in. adjustable rubber 
bumper E beneath the press places enough pressure on the pres- 
sure pad F in the die to prevent wrinkles forming in the blank. 



DRAWING SHEET METAL INTO SHAPES 



79 



This insures a shell that is of uniform thickness and straight 
edges that need no trimming. 

The second and third operations will run in one press with 
the dies and punches, Figs. 108 and 109, fastened side by- 
side and adjusted to give each operation the desired pressure and 
at the same time to equalize the pressure on the press to 
prevent press trouble. 

The second and third operations are formed in dies with 
knockouts to prevent the pulley from sticking in the die, thereby 
allowing the operator to quickly transfer it from one die to the 























j | 




I 


i 


i 


f 




1 


1 


t i O i '" i! 


I ; 


!| 




J L J { 






J---h«:r-i 


















" 




n 












r ~i 










<-\—j-, 




J3 






i 


a 


! G\ 




■ 1 




% if L b T — i — -j — t^ i 




1 ' ' ll 


u, ." ___ 



W 



tST 




Fig. 108. — Second and third operations- 
tandem dies and punches. 



Fig. 109. — Fourth operation 
— die and punch. 



other and at the same time supply the first die again. The 
knockout is positive; it is controlled by two %-in. rods screwed 
to the ram, passing through the bolster plate, and fastened to the 
kicker on the bottom of the die. 

The third operation bevels the pulley %2 m - a * one side of 
the crown and punches out the bottom. This die has a cutting 
die G beneath the drawing die. The draw punch H is 34 in. 
longer than the desired length of the hub and has }i-in. radius 
on the end, which prevents the metal from stretching but punches 
out the bottom when the hub of the pulley comes in contact 
with the cutting edge of the die G. The edge will be a feather- 
edge, but this is taken care of in the succeeding operation. 

The stretch in this hub is small, and when the die and punch 



80 



PRACTICAL DIE-MAKING 



are kept smooth, the walls of the hub will not be over 0.006 
in. thinner than the original thickness. This is considered very- 
good where a large production is desired and where 0.006 in. 
on the outside of the hub is of little account. 

The fourth operation puts the bevel on the opposite side, 
thereby finishing the crown, and at the same time sizes the hub 
and bevels the feather edge caused by punching out the bottom 
of the hub previously. 

The hub is sized to \%2-m. inside diameter, the sizing punch 
being 0.008-in. taper. 










1ft" 


":.;£". 


IM 




1\ 


-* W' 



Fig. 111. 
Figs. 110 and 111. 



Fig. 110. 



-A drawing punch and die. 



A Drawing Punch and Die. — In the accompanjdng illustrations 
is shown a novel method of constructing a blanking and form- 
ing die, whereby the work is produced in one operation on a 
single-action press. 

At A, Fig. 110, is shown the blank produced by the first action 
of the punch on the sheet stock; at B is the result after the 
inner punch has pierced the hole and at C is shown the completed 
piece, after the outer punch has formed the shell to the required 
shape. 

The construction details of the punch and die are shown in 
Fig. Ill where A represents the die-shoe which is bored to 
receive the die plate B which is pressed into A and held in 



DRAWING SHEET METAL 



81 



place by the two dowels C,C. The die-plate B is counterbored 
in its lower end to receive the pressure ring D and is bored in 
its upper end for the diameter of the blank which it is required 
to produce. At E is shown the punch which fits into the punch 
holder of the press and is used to produce the outside diameter 
of the blank, while F represents the inner punch which pierces 
the required hole in the blank. The tension pins G,G are held 
against the pressure ring D by the action of the tension spring H. 
The former J is bored to permit the scrap produced by the pierc- 
ing operation passing through and dropping into a box on the 




Fig. 112. — Stages of drawing a fan pulley. 

floor. Its upper end acts as the die for producing the inner 
diameter of the pierced blank. 

The stop K is held in position by the setscrew L and makes 
contact with the stock on the blanked hole produced in the 
scrap which has passed the die. The stripper plate M is held 
by two screws and dowels, as shown. The positive knockout 
N is a sliding fit in the punch E, having adjusting nuts on its 
upper end which govern the depth of its movement. 

In operation, the stock is fed against the stop K and the 
punch descends and blanks the outside diameter, the stock being 
supported by the pressure ring D so as to prevent buckling or 



82 



PRACTICAL DIE-MAKING 



wrinkling. As the stroke continues downward the inner punch 
F pierces the inner hole in the blank and continuing to its lowest 
position forms the metal to the required shape. In ascending, 
the positive knockout N strikes a stop which forces the knockout 
downward and ejects the work. 




Drawing Dies for a Fan Hub. — As it is rather difficult to draw 
a small hub on a large disk, this article may be of use to those 
who have similar work to do. 

In Fig. 112 are shown the shapes of the samples in consecutive 



DRAWING SHEET METAL 83 

stages. The disk used is of 10%-in. diameter. The first opera- 
tion reduces it about ^ in. in diameter and raises the hub shown 
as far as the metal will go without straining it. The metal is 
ordinary cold-rolled steel plate 0.078 in. thick, and not special 
drawing stock. The dies might possibly have worked better 
if they had had hardened-steel drawing edges, but as they were 
for a limited production, they were made of cast iron. 

In Figs. 113 to 118 are shown the tools for the six operations 
necessary. 

After the last forming operation, a soft-steel insert is made as 
shown in Fig. 119 and pressed into one side; the other side is 
then pressed onto it. The hub is placed between the points of 
an electric spot-welder and welded at about four places. 

The ends of the steel insert are next beaded over with a 
beading punch and die, after which the hub is drilled and tapped 
for setscrews. It is then punched for the blade rivets, when it 
is ready for assembly into the fan wheel. 

Making a Fuse Clip. — The following illustration shows a 
modern method of making the fuse clip shown in Fig. 120. 

Individual Dies and Operations 

The vital points of this clip are the sides A, A, which fit into 
the terminals, and to insure good contact they have a certain 
amount of spring. The fuse ribbon is attached to B. The 
edges clamp it so that solder connections are easily made. A 
simple blanking die is shown in Fig. 121. To obtain the spring 
action mentioned, the blank is cut so that the grain of the copper 
runs lengthwise. The other sides do not require this spring 
action. 

The die for the second operation is shown in Fig. 122. It 
is a piercing die of simple construction, with two bushings set 
in the bolster. This piercing die is used so that the blank will 
shear properly when in the die, Fig. 123. 

In this operation the cuts are made in line with the edges of 
the pierced holes, the parts are also bent downward in this die and 
the gaging is done at the same points as in Fig. 122. The punch 
(not shown) has a spring pad attached to prevent the blank from 
sticking to the punches. No stripper is necessary for the die, as 
the turned-down ends have a tendency to spring out slightly and 
release themselves. 



84 



PRACTICAL DIE-MAKING 



The tools for the fourth operation shown in Fig. 124 are for 
closing the ends, as shown at B, Fig. 120. The side with turned- 
up ends is placed under the forming die A, Fig. 125, and closed 
with the punch B. 

In Figs. 126 and 127, the last operation is shown. This forms 
the piece to the proper shape. The gaging is clone from the four 
corners as shown in the illustration. The die has a spring pad, 
which holds the blank and prevents it from buckling when the 



P 

A H2j A 

Fig. 120. 





10 ° 




r o 



Fig. 121. 



Fig. 122. 



1 


O o 

01 O jo 










k 


-f Q- 





















e> 


~ r if 





Fig. 123. 



Fig. 124. 



Fig. 126. 






On 



Fig. 125. 
Figs. 120 to 127.- 



1 a 

Fig. 127. 
-Dies for making a fuse clip. 



punch enters. To prevent it sticking to the punch, a spring pin 
A is used. The sides A,A, Fig. 120, have no tendency to hug, 
owing to the grain of the metal, but the opposite sides, not having 
this spring, will at times cling, especially if the metal is slightly 
thick. Sharp corners must also be avoided, otherwise fracture 
is liable to occur. 

The Gang Die 



In order to increase production, the die shown in Figs. 128 and 
129 was designed. All the operations previously described and 



DRAWING SHEET METAL 



85 



illustrated are taken care of with this tool. By referring to the 
broken outline AA, Fig. 128, the method of operation is shown 
progressively. The stock enters at the gaging point BB as far 
as C, when the first operation is performed; namely, cutting the 
corners and piercing the holes at D. The next step is to move the 
strip to the point E where the gage F is pushed forward to locate 
properly the cutting and bending of the ends at G. At the same 
time the corners are cut and the holes D pierced. The strip 
is again moved forward to the point F and four operations are 

Fig. 128. 




Fig. 129. 
Figs. 128 and 129. — Gang die for fuse clip. 



performed, the third closing the ends H and cutting off at L 
The last move is to bring the stock to the gage K. At this point 
the piece is folded and the other operations are done simul- 
taneously. The push gage F is used only when starting a new 
strip. The spring keeps it in proper place. 

At Fig. 129 is shown a side view of the punch and die and the 
cross-sections are of the principal points, such as the piercing 
punches D, which engage at D, Fig. 128. Also the punches G 
corresponding to G, Fig. 128. The stripper L, Fig. 129, prevents 



86 PRACTICAL DIE-MAKING 

the work from sticking to G. The stripper M embraces the 
punches D,N,N. The closing die is shown at H, the cut-off 
punch at I, and the folding punch at R. 

A pressure pin S assists in holding the work securely while the 
cut-off punch severs the blank from the rest of the strip. The die 
is of pillar construction, making it self-contained. The punch 
holder and the bolster are of machine steel. Dies are sectional 
where permissible, making the up-keep, repair, and the like, easy- 
tasks. 

The actual costs of the dies are not available, but the first set 
cost in the neighborhood of $85 and the gang dies about $130. 
The production with the individual dies was about 150 finished 
pieces per hour. With the gang die the production is easily 
brought up 1000 finished pieces per hour. 

Thus with an increase in cost of a little over 50 per cent, for 
the gang dies, we have an increase in production of nearly 600 
per cent. 

Making Sheet-metal Boxes. — In making sheet-metal boxes 
such as are used for protecting electrical installations consisting 
of cutouts, switches, fuses, etc., good judgment is essential in 
designing the necessary tools because first cost is generally 
considered an important factor. 

The numerous different designs and sizes, varying in length, 
width and depth, make the problem of manufacture an interest- 
ing one, especially when the quantity produced of any one kind 
is small. The construction of proper dies in such cases would 
be prohibitive because the tools would probably never repay their 
cost. Therefore, to produce the boxes in question the equip- 
ment regularly used generally consists of notching, corner-cut- 
ting and piercing dies for the blank, and a break or bending 
machine for forming or folding the box. 

In order to explain the method more fully the accompanying 
illustrations will assist in describing one way of making a sheet- 
metal box from material about }{q in. thick. 

The box shown in Fig. 130 is rectangular and the corners 
must be tight; that is, no opening or crack is permissible at A. 
The development of the blank is made apparent in Fig. 131, which 
shows the proper allowance made for the lap A , which is bent up 
at a right angle before folding the sides of the box. This lap is 
afterward spot-welded to the proper side, making a closed corner 
as shown in Fig. 130. 



DRAWING SHEET METAL 



.87 



Proper Mass-production Method 

To produce boxes in quantities the proper way would un- 
doubtedly be to make one blanking die, one piercing die, one lap- 
or ear-bending die and one folding die for each size box, in order 
to minimize the operations, handling of stock, etc. Assuming, 
however, that conditions are otherwise and that a variety of sizes 
is wanted, it will readily be seen that it would not be profitable 
to construct individual dies for each size. Therefore, it is 




Fig. 130. 



O 



o © 



o O 



Fig. 131. 




Fig. 132. 



Figs. 130 to 132. — The box, blank and notching die. 

necessary first to consider the tool cost and to provide a set of 
tools that can be adapted for all sizes within a reasonable range; 
hence, the following method is more practical. 

The stock is sheared to correct size and a corner-cutting die, 
as shown in Fig. 132, is used for notching the corners. The 
opening is large enough for notching the blank for the box with 
the greater depth. 

A machine-steel bolster on which the tool-steel die is mounted 
is so arranged with the adjustable gages C and D as to properly 



88 PRACTICAL DIE-MAKING 

facilitate gaging the blank, which is shown in broken outline. 
The gage D has rests E for supporting and assisting in holding 
the blank flat. 

The boxes are generally provided with various holes and open- 
ings on the bottom and sides for fastening to walls or meter boards, 
also openings for conduits and cables. These holes are pierced 
before folding the box, and individual dies are used, having proper 
locating gages attached to facilitate rapid operating. 



Work, 



v 



Fig. 133. 



IZJ 



s 

A 


C 


f - 


D 

® 

% 


6 

— ., 

B 


e ! E i © 


9_I L& 


e !f! i 


i i 

.—J L. 



Fig. 134. Fig. 135. 

Figs. 133 to 135. — Dies for bending and cutting corners. 

Owing to the size of the sheet and the different locations of the 
holes, the piercing dies are made on the style of a bushing, in- 
serted in the bolster and held in place with a set screw, the 
stripper being attached to the punch. After the holes are 
pierced the laps, or ears, are formed, using a break or bending 
machine similar to the design shown in Figs. 133 and 134. Ar- 
ranging the dies as indicated in Fig. 134, the ears can be bent on 
the dotted lines F of the blank shown in Fig. 131, two ears being 
bent at one stroke, thus completing the bending of the ears in 
two strokes. 

Folding 



The folding operation is done in the same machine, and when 
space permits and with proper arrangements of the dies, the ear- 



DRAWING SHEET METAL 89 

bending and folding can be completed in one handling, making 
six strokes of the machine for each box. Generally, a number of 
dies of various widths are kept in stock so that a number of 
different combinations can be arranged. With this tool equip- 
ment a variety of sizes of boxes can be made, but the cost of 
production is high. Although the problem of handling the pieces 
has been considered, the operations are necessarily slow, and the 
larger the sheet the slower the production, on account of the 
different movements necessary in handling. 

In order to improve upon the method described, the factor of 
handling the product must be considered first; the problem re- 
solves itself into making'fewer strokes of the press in producing a 
box and still keeping the tool cost down as low as is consistent 
with the quantity required. 

The following illustrations show adjustable dies which have 
been found of great assistance in speeding up production and 
reducing manufacturing cost. 

The corner-cutting die is shown in Fig. 135 doing the same 
work as shown in Fig. 132. Two operators are required, one in 
front of and the other behind the press. In starting, the operator 
in front cuts his sheet and pushes it through to the second 
operator, who cuts his side at the same time that the first, 
operator is handling his next sheet. 

One notable feature, besides producing one piece at each stroke 
is the simple method of handling the stock. No awkward turn- 
ing movements are necessary, one operator simply puts the blanks 
in the press and the other takes them out, and where a conveyor 
scheme is used for removing the finished blank, the stroke of the 
press becomes as regular as clockwork. 

Sectional Die 

In its construction the die shown in plan in Fig. 135 is composed 
of sectional pieces fastened to a bolster plate. The stationary 
pieces A, B, C and D are doweled and screwed fast with fillister- 
head screws. The adjustable pieces E and F have oblong slots 
for the screws, and, to insure the dies from shifting, adjustable 
stops are provided which act as braces. To adjust for the 
different sizes, the pieces E and F are moved in or out, as are 
also the side gages G and end gages H. 

The punches (not shown) are also fastened to a plate, adjusted 



90 



PRACTICAL DIE-MAKING 



and braced similarly to the dies E and F. They are ground 
taper to produce a shearing cut and the heel is made sufficiently 
long to allow it to enter the die far enough to insure rigidity 
during he cutting. 

With the piercing dies the same scheme is used as before, there 
being no other practical method whereby all holes can be punched 
at one stroke of the press. 

For bending the ears so that one blank is produced at each 
stroke of the press, the same principle is used, that is, two opera- 
tors to one press. 

Besides being more accurate than the bending machine, it 
will be noted that adjustments for the different sizes are equally 
rapid. 



I 



--'"}- 






E 



Fig. 136. 

F E&.-D C, E F 




IT 



L_ 



J ,] 



m 




O 



Fig. 139. Fig. 138. 

Figs. 136 to 139.— The improved dies. 



The die is clearly shown in Figs. 136 and 137. At A is the 
bolster to which the dies B are fitted, their ends machined taper 
or dovetailed to fit the bolster. Each has a recess at C which 
acts as a gage for the blank, and also a spring pad D which tends 
to hold the blank flat when bending the ear. Setscrews in the 
dies E and the stops F prevent shifting. 

The punch (not shown) is constructed on the same plan 
except that the stop screws are placed in the center of the holder 
instead of the ends, as in the die. The punches tend to shift 
inwardly while the die tends to shift outwardly. 



DRAWING SHEET METAL 91 

Folding Operations 

For the folding operation the die shown in Fig. 138 is used. 
Besides being very simple in construction, the great range of 
adjustment makes it valuable, and it would be universal in its 
scope but for the fact that a separate punch plate and spring 
pad must be provided for each size. These, however, are made 
very cheaply, generally from cold-rolled flat stock, requiring no 
machining except on the sides and ends. Referring to Fig. 
138, the four hardened-steel strips are shown in the arrangement, 
held in place by the clamps A, which are backed up by ad- 
justable stop-screws. 

The bolster is provided with a rubber to actuate the spring 
pad. As a new pad is made for each size, it is an easy matter to 
set up a job. The method of procedure is to place the pad in 
the center of the bolster and place the die strips around it. 

The punch is shown in Fig. 139. The plate is supported by 
the studs which are screwed in the holder, which is always 
fastened to the head of the ram. Additional holes are tapped 
in the holder for the different locations of the studs as the sizes 
vary. 

Boxes made from zinc are extensively used in protecting in- 
stallations, especially when inclosing the meter and cutout, 
and considerable trouble is often encountered in folding the 
box. The sides often break entirely off or fracture on the bend- 
ing line, especially so when running with the grain. This 
fact is more noticeable when the metal is cold, so to eliminate 
breakage as much as possible, the blanks are placed in hot water 
or some heating apparatus convenient to the operator. 

Press Tools for Making a Swivel. — The tools shown herewith 
were designed for making the swivel ring for a small lot of swivel 
hooks used on dog leashes, swords and the like, as shown in 
Fig. 140. 

An end elevation of the press tools used to form the double 
ring on top of the large ring is shown in Fig. 141. The wire is 
first cut and bent U-shaped, as shown at Fig. 143. It is placed 
between the jaws A, B, Fig. 141, then the handle C is brought 
over locking the U-wire in the vise, so that it can be formed 
round the piece D and the tit H by the punch E, which is brought 
down on the die and turned round by hand with the aid of the 
bar F. The punch is then raised and brought sharply down to 



92 



PRACTICAL DIE-MAKING 



flatten the double ring on top, leaving it as shown in Fig. 144. 
When the locking handle C, Fig. 141, is released, the vise is 
opened by the action of the spring G; the iron- wire ring is then 
quite easily removed by hand. 

A plan of the tools is shown in Fig. 142 with the vise locked 
on a U-shaped wire ready for the punch E, Fig. 141, to be brought 
down. The tit H on the end of punch E enters the hole J and 
the. wire is formed round it by the two projections K,K, which 
draw the wire toward the center pin N and then continue to 










m 




\ 







h 



Fig. 142. 



Fig. 141. 

Figs. 140 to 144. 



Fig. 143. Fig. 

-Tools for making a swivel. 



144. 



turn the ends of the wire around the pin. The ring is made 
from soft-iron wire 0.1 in. diameter and is cut and formed on a 
standard four-slide wire-forming machine running at 120 r.p.m., 
and finished on a press at the rate of 25 per minute. The total 
cost of the tools was $20. 

The same job could be made in one operation at a little 
extra cost for tools on a standard automatic wire machine 
at the rate of 100 per minute. 

Making a Small Forming Die. — The punches and dies here 
illustrated were to turn out the piece shown in Fig. 145 and 
were to be formed in a hand press as in Fig. 140. 



DRAWING SHEET METAL 



93 



The cup-shaped piece, Fig. 147, was first made of hardwood. 
This was rilled with plaster of Paris and while soft the model 
(which had been submitted with the job) was pressed into it, 
centralizing by marks, as indicated at A in Fig. 146. When 
the plaster had set, the model was taken out and the mold 
trimmed up smooth on top and edges with a file, it was then 
sent to the foundry, where a fine iron casting was made from it. 
This was smoothed up in the form and machined where indi- 
cated. Two countersunk holes for fastening to the press were 
then drilled, as shown. This completed the die. 




Fig. 146. 



Figs. 145 to 148. — Making a small forming die. 

The piece shown in Fig. 148 was then made from a hardwood 
block, turning the stem to fit the hole in the spindle of the press. 
The die was next set into place in the press and a piece of card- 
board wound around it and held with a rubber band to form a 
cup. The model was next placed in the die and after placing 
the piece shown in Fig. 148 in the spindle, plaster of Paris was 
run into it and allowed to set. The die and model were oiled 
so that the plaster would not stick to them. The plaster was 
anchored to Fig. 148 by two large-headed tacks shown at B. 
Some thick paper was then glued to the stem of the punch to 
allow for small finish. This was sent to the foundry and cast 



94 PRACTCIAL DIE-MAKING 

of fine iron. It was then smoothed and finished in the same 
way as the die, care being taken that the stem ran true before 
turning. It was next placed in the spindle with the die and 
model in place and spotted for the setscrew point at C. By this 
method a very satisfactory job was turned out. 

Reinforcements for Tapped Holes in Brass. — In the production 
of electrical appliances, instruments, supplies, and the like, which 
are made of sheet metal and have holes pierced in the punch 
press, which must later be tapped, some trouble will be en- 
countered when it comes to using stock less than }{q in. thick, 
especially if the tapped hole must resist any strain. In order to 

Piercing Punch 
"Diam.of inpno/e 
r 'Diam. of Teaf 




Diam. of 
reinforcement in 
diep/afe 

Fig. 149. — Reinforcements for tapped holes. 

provide the greatest possible thickness of metal to tap through, 
the stock is pierced and the punch which does the piercing 
has an enlargement which passes down through the metal far 
enough to force the metal out on the under side, forming a re- 
inforcement or greater thickness for the tapping of the hole. 

In the illustration, Fig. 149, are shown the type of punch used, 
at A ; at B, the hole in the die-plate, and at C a section of the metal 
after the punching and forming has been completed. The 
size of hole in the die-plate governs the outside diameter of the 
reinforcement. 

The dimensions given in the table have been found to give 
excellent practical results in the tapping of holes in half-hard 
brass. The dimensions for the tapped holes required, the 
diameter of the piercing punch used, the diameter of the form- 
ing portion of the piercing punches and the outside diameter 
of the reinforcement when finished, are given for brass 0.031 
in., 0.400 in. and 0.050 in. thick. 

Others feel that where a long draw is required (say over twice 
the thickness of the metal), a single drawing punch as shown 
is apt to crack and break the edge of the draw as shown in Fig. 
150, herewith. 



DRAWING SHEET METAL 



95 



Size of 


Diam. of 

tap hole, 

inches 


Diam. of piercing punch, inches 


Outside 
diam. of re- 


tap 


0.031 brass 


. 040 brass 


0.050 brass 


inforcement, 
inches 


3-48 


0.082 


0.045 


0.052 


0.060 


H2XH2 


4-32 


0.087 


0.053 


0.060 


0.068 


M2XM2 


4-36 


0.093 


0.063 


0.070 


0.078 


H2XH2 


5-40 


0.105 


0.071 


0.078 


0.086 


%2 XM2 


6-32 


0.113 


0.079 


0.086 


0.094 


H2XH2 


7-32 


0.128 


0.087 


0.094 


0.102 


M2XM2 


8-30 


0.138 


0.095 


0.102 


0.110 


% 2 xy 32 


8-32 


0.141 


0.103 


0.110 


0.118 


M2XM2 


3-48 


0.082 


0.043 


0.050 


0.058 


%X^2 


4-32 


0.087 


0.051 


0.058 


0.066 


%x^ 2 . 


4-36 


0.093 


0.061 


0.068 


0.076 


^4X^2 


5-40 


0.105 


0.069 


0.076 


0.084 


^4X^2 


"6-32 


0.113 


0.077 


0.084 


0.092 


11 A4xy 32 


7-32 


0.128 


0.085 


0.092 


0.100 


xl A±xy 32 


8-30 


0.138 


0.093 


0.100 


0.108 


x y±xy 32 


8-32 


0.141 


0.101 


0.108 


0.116 


^4x^2 


3-48 


0.082 


0.041 


0.052 


0.056 


HeXH 2 


4-32 


0.087 


0.054 


0.059 


0.064 


Hexy 32 


4-36 


0.093 


0.059 


0.066 


0.074 


Y\eXy 32 


5-40 


0.105 


0.067 


0.074 


0.082 


HeXH 2 


6-32 


0.113 


0.075 


0.082 


0.090 


Hexy 32 


7-32 


0.128 


0.083 


0.090 


0.098 


HeXH 2 


8-30 


0.138 


0.091 


0.098 


0.106 


He X}i 2 


8-32 


0.141 


0.099 


0.106 


0.114 


Hexy 32 


3-48 


0.082 


0.051 


0.058 


0.066 


HeX%i 


4-32 


0.087 


0.059 


0.066 


0.074 


HeX%± 


4-36 


0.093 


0.069 


0.076 


0.084 


HeX%4 


5-40 


0.105 


0.077 


0.084 


0.092 


HeXVe* 


6-32 


0.113 


0.085 


0.092 


0.100 


HeXYe± 


7-32 


0.128 


0.093 


0.100 


0.108 


HeX%4 


8-30 


0.138 


0.101 


0.108 


0.116 , 


HeXK* 


8-32 


0.141 


0.109 


0.116 


0.124 


HeX% 4 



Reinforcements for Tapped Holes 



Brass 



This breaking is overcome by making the drawing punches as 
shown at Fig. 151, the number of steps depending upon the size 
of hole and depth of draw required. In fact, this is the only 



96 



PRACTICAL DIE-MAKING 



shape of punch that gives satisfactory results in drawing holes 
in all metals, and it is useful where a boss is to be drawn in a large 
sheet of metal. In small work this type of punch will pierce first 
and then continue drawing the hole it has pierced in one opera- 
tion, but in other than small work it is best to make the piercing 
and drawing separate operations. 

In Fig. 152 is shown a plan and elevation of a brass ring to 
which three small springs had to be assembled; they were pre- 
viously assembled by piercing six holes in the ring and assembling 
the ring and springs by using eyelets. By using the same pierc- 




Fig. 151. 



Fig. 152. 



ZS 



Fig. 153. 



' -^^| 



^— pzzz 



Figs. 150 to 153. — Other methods of reinforcements. 



ing tool and only changing the punches the projections were 
drawn from the ring as shown at Fig. 153. These projections 
took the place of the eyelets and made the assembling much easier. 
The thickness of the ring was 0.04 in., thickness of drawn pro- 
jection 0.02 in. and the depth about 0.1 in. The drawing punches 
in this case had four steps or sizes on each, allowing the lengths 
of draw to be such that no two sizes were being drawn at the 
same time. 

In drawing steel greater care has to be taken to prevent the 
open edge of the hole cracking, and usually a greater number of 
drawing edges on the punch are desirable and the shape and size 



DRAWING SHEET METAL 



97 



of the radii are important, while the annealing of the pierced hole 
is an advantage in deep drawing. 

In Fig. 153 is shown how the two kinds of punches act upon the 
stock or pierced hole. It is easily seen that there is a great sudden 
strain upon the metal with the single punch, which has a tendency 
to crack the edge of the hole before it draws, while with the multi- 



Wj^ Section X-Xr> 

Part to be Made FlG - 154 - 




*0.<W 



Spring. 



Die Holder 



Fig. 155. 



Fig. 156. 
Figs. 154 to 156. — Still another reinforcement. 



size punch it is only a small amount of metal round the hole that 
is influenced; it is, in fact, an expanding punch which draws. 
A taper punch has no better effect than the radius-end single- 
size parallel punch. 

Another die made to bend and draw a reinforcement so as to 
give more thread room is shown in Fig. 156. 

The part is shown in Fig. 154 with the drawn portion and the 
increased thread space in comparison with its thickness of stock. 

7 



98 PRACTICAL DIE-MAKING 

In the perspective view one side leg is removed to show the drawn 
boss. 

The sequence of operations necessary to manufacture this part 
is: First operation, blank and pierce all holes; second operation, 
bend and draw the boss for the tapped hole; third operation, tap 
the drawn hole. 

Fig. 155 shows the stock layout for the blanking and piercing 
die; the size of the hole Y determines the length of the drawn boss. 
If this hole is made large the drawn boss will not be long and, again, 
if the hole is small you can obtain a longer boss, because it is the 
amount of metal left after you pierce the hole which determines 
the length of boss. 

Fig. 156 shows the punch and die with the part in position 
completely formed and with the correct size of hole correspond- 
ing to the proper tap-drill size for the tapping operation. 

One of the blanks is shown at A ; at B are two pins with springs 
to operate the pressure pad. These have two projections C, 
one on each side, which stop against D in the cut-out portion E 
in the plate F. There are two of these plates secured to the side 
of the die, which retain the pressure pad. The pin G draws the 
boss and is provided with a point to enter the pierced hole. The 
pin H in the punch removes the completed part. 

Pressed. Versus Machine-finished Parts. — In the manu- 
facture of interchangeable parts, used in the assembly of adding 
and addressing machines, registers, scales, typewriters and the 
like, in which a large quantity of duplicate parts of a tubular 
or hollow cylindrical form are used, which must be not only con- 
centric but interchangeable, and yet low in production cost, it 
becomes quite a problem for the shop superintendent to decide 
which is the best, quickest and cheapest way to produce such 
parts. 

If the quantities required are small, say not over 1000 pieces 
per lot and the lots are far between, and if cheapness need not 
be a prime factor in his calculation, the superintendent will in- 
variably decide in favor of screw machines, either automatic 
or hand operated, and it depends largely on the condition of 
these machine tools, the skill of their operators and the stringency 
of the inspection limits how large a percentage of perfect, thai is. 
interchangeable, parts will be obtained from a given lot. 

Another reason why screw machines are generally favored for 
this class of work is because of their adaptability to various forms 



DRAWING SHEET METAL 



99 



of cylindrical work without a great investment for special tools. 
A nominal figure for forming tools and reamers is all that is 
reckoned. This factor is, perhaps, the trap in which many other- 
wise shrewd shop managers are caught; they see only the low 
initial cost for tools, but overlook entirely the loss per lot due to 
slow production, to work spoiled or not passing inspection, and 
to the fact that their screw-machine department becomes over- 
taxed with work that could be done advantageously with special 
tools in punch presses or with special machinery. They deprive 
themselves of the use of their screw machines and millers for work 
that cannot be done to good advantage in any other way. 

Examples of the Work 

The drawings will furnish an instance of this. 
Fig. 157 represents a hollow shaft with slots running parallel 
to its axis. Fig. 158 shows a slotted filler for Fig. 157. Fig. 159 



7 " ' $ " 3" s" 



<M> 



^■->f377 t 



■4i" -»™-"l J ---^j»- 



04395 



-1—.-UI— -V 



3 C^D 

~.~7j 




J ..^o.soo^... 

* 0.4395^ 



B 

Fig. 157. — A slotted hollow shaft. 



is a view of a spacer tube, and Fig. 160 illustrates a threaded 
housing for a ball race. 

After a superficial examination of the illustrations nearly every 
practical man would assign these parts to the screw machines 
for the first operation, to be followed, where required, by a 
slotting operation on the miller. In fact these parts had been 
made for years in just this way in one factory until it was realized 
that they were costing considerably more than their allotted al- 
lowance in the assembly of the machines. 

On account of the close limits on length and concentricity of 
the outside with the hole, the inspection loss had been great and 



100 PRACTICAL DIE-MAKING 

the time of production slow, so that the screw machines fell be- 
hind with other work. This necessitated working overtime and 
even night shifts at higher wages. This meant an increase of 
pay-roll, an increase of power and light bills and raised the entire 
overhead charge, directly affecting the production cost of the 
screw-machine department in total. 

The parts shown by Figs. 157- A and 159- A were made of seam- 
less steel tubing of sufficient wall thickness to allow machining 
of the pieces both inside and outside. The hole was first bored 
and reamed to size, but since tubing of such wall thickness could 
not be secured absolutely true and the drill and reamer followed 
the old hole, subject to the law of least resistance, it was im- 
possible to get concentric work until the outside surface was 
finished in a later operation by driving the pieces on arbors and 
turning them between the collet and center. By this method 
true work was obtained, but the finish depended on the sharpness 
of the cutting tools and the cutting speed of the machine. Any- 
body acquainted with the machining of unpickled steel tubing 
knows what that means. 

A Change in Material 

Finding this method unsatisfactory a change was made in 
the material and the parts made of cold-drawn steel stock of the 
largest diameter of the finished pieces, depending on the accu- 
racy of the stock for the outside surface, the size of the reamer and 
copious lubrication for the size and smoothness of the bore. It 
also depended on good luck for the trueness with which the drill 
and reamer would come out on the other end, or rather meet in 
the center (inasmuch as the automatics had onfy a 2-in. feed and 
it was necessary to add another drilling and reaming operation 
on a hand machine). 

On account of a lower price for cold-drawn stock as compared 
with steel tubing and because the machining of the outer surface 
of the hollow shaft, Fig. 157-A, was omitted, the final cost of these 
pieces was about one-third lower as made of cold-drawn material 
in the manner last described than when made of tubing, in spite 
of the additional drilling through the center. However, even at 
this reduction the price was too high because of the large inspec- 
tion loss due to eccentric work, as well as to rough or oversize 
holes. 



DRAWING SHEET METAL 101 

The part Fig. 160 was also made of cold-drawn stock, on an 
automatic. The thread had to be absolutely true with the 
bore and was chased on the lathe as indicated in Fig. 160-^L 
The part Fig. 158-A was made of special gaged cold-drawn stock 
cut off on a hand screw machine and then slotted and milled at 
great expense in two operations. 

The drawings marked B, showing these parts somewhat 
modified in their appearance but serving the identical purposes, 



0.126", 
0.125 •> 

■nr 



^x_d %kJ 



_ u— 



*l #V L>l ; K ~ 



..>| 0.374", 

0.3755 






L ...... 4 2>L -d V, V 

rr-i i — v i — i g r—> i — Q ^#ww 



ASSEMBLY 



■•# 



-^S,..^ " " . B 



ffl J 






! 
Fig. 158.— Slotted filler for hollow shaft. 



will show clearly how they finally dispensed altogether with 
the expensive screw-machine and milling operations. This left 
these machines available for other jobs, thus cutting out ex- 
pensive overtime and night work and incidentally reducing the 
cost of the products to a surprising extent. 

They are now making part Fig. 157-Ain one-tenth, part B at less 
than one-tenth, part Fig. 158-1? at one-fourth, and part Fig. 159-A 
at one-third of their former costs and the products are finished 
better now than when made under old conditions. 

Greater Economy and a Better Product 

It will be noticed that all of these parts, with the exception 
of B, Fig. 158, which is die formed of seamless steel tubing of a 



102 



PRACTICAL DIE-MAKING 



gage to give correct diameter at the shoulders and requiring 
no machining or finishing, are now formed of cold-rolled, open- 
hearth strip steel in special dies and require little or no machin- 
ing. In spite of their great cheapness the pressed products 
are far more satisfactory and uniform, and therefore inter- 
changeable, than were the expensive machined pieces. An added 
advantage of the pressed pieces is their smoothness and wear- 
ing qualities, due to the rolled surface of the raw material. 
The transformation of this production from bar steel on 
the screw machines to cold-rolled strip steel, formed to shape in 
special dies in the punch press, required an investment of about 




*r 



Hr. 



2.010 
"2.0JZ r 



"W 






Countersink \---^l\<- 

U ---• 



64 




EzJ^ 



zz^yp 



rTT',/, ,'i— i 



7'tttt; '- - 






Burr 



Fig. 159. — A spacer tube. 



$500, but the saving on the first lots repaid this expenditure and 
left a profit besides. 

The examples given in the preceding, while based on facts, 
are by no means suggested as a criterion by which other con- 
ditions should be regulated; they merely express one man's 
opinion and illustrate how one firm dealt with perplexing con- 
ditions and remedied them to their entire satisfaction. 

Making a Pressed-steel Bicycle Hub. — The pressed-steel 
bicycle hub is drawn from a 4}^ -in. blank of 18-gage cold-rolled 
steel, but can also be made from 18-gage seamless tubing, thereby 
eliminating the first three press operations and making it possible 
to complete this hub in four operations. It is more economical 
to make them from annealed seamless tubing, if one considers 
the cost of dies, punches, labor, steel, presses, etc. 



DRAWING SHEET METAL 



103 




r-^J 1<- -2f 

B 
Fig. 160. — A threaded-ball race housing. 



104 



PRACTICAL DIE-MAKING 




-£■ 






U-. .--%?— 


~J 


•^ 




[ 




—s — 


—*j 


* 1 


) 




k~- 


-JB&r*- 


— >l 






<o 


L L -----_---_-_------_-_-_-^ :; 



.2 >\ 





"h 

> 1 UJ 

j 1 
1 1 
.l_J 


I s 

/ «-> 

r r 
'"> 

r 













a. [jj 
O ^ 

6 



DRAWING SHEET METAL 105 

Hubs made from cold-rolled steel have a better appearance 
and are finished more easily for the nickel plater. The opera- 
tions are shown in sequence in Fig. 161. 

The first operation is blanked on a double-action press. This 
press will give greater satisfaction and a greater production than 
a single-action press and a compound die. When using a 
compound die, the press must be stopped to remove each shell, 
whereas with a double-action press the shell is drawn through 
the die, dropped into a receptacle under the press and auto- 
matically conveyed to the next press, where it is run through the 
second operation. The press can, therefore, be run continuously 
on each sheet of stock. 

First Operation 

The first-operation die and punch are shown in Fig. 162. The 
drawing punch A and the drawing die D are of high-speed steel. 
While ordinary tool steel will do, it wears faster and develops 
scratches oftener than high-speed steel, making it necessary to 
stop the press and polish the die and punch. It will be found 
that high-speed steel gives greater satisfaction, the upkeep 
costing less and the production being greater. 

The blanking punch is shown at B. The blanking die C 
is set in a cast-iron plate with the drawing die D set underneath 
it; these are held together with flat-head screws F. 

Air holes are provided in the punches of the first, second and 
third operations. It costs little to put these air holes in punches 
and there is great saving on stripper repairs, as punches with air 
holes strip the shell more easily. 

Second Operation 

The second-operation tools, shown in Fig. 163, consist of 
a straight punch and round die set in a die holder G in the 
manner shown in Fig. 164. The punch A has a hole through the 
shank to secure it by means of a through pin B, Fig. 164. 

The inserted die B, Fig. 163, is cheap and lasting, as com- 
pared with a large solid die, because it can be shrunk and brought 
back to size a number of times. It can be replaced in a few 
seconds when it becomes necessary, and does not require as 
much material as a solid die. Its great advantage over the 
solid die is the facility with which it can be replaced, thereby not 
holding up production. 



106 



PR A C TICAL DIE -MA KING 



The third-operation shell C, Fig. 161, has no bottom. It 
is perforated on an underhanging perforating die shown in 
Fig. 165 at C. The body A is set underneath the third-operation 
die and fastened with capscrews to the bolster plate at B. The 
perforating die C is set into a large adjustable retainer D, and 
can be adjusted to let the drawing punch C, Fig. 164, perforate 
the bottom of the shell after drawing it through the die D, 
Fig. 164. When the shell is stripped from the punch, it is gently 
thrown out of the way of the succeeding shell by the spring E, 
Fig. 165. 

The dies for the third operation are the same as those used 
in the second. When the diameter of the punch is less than 



— ! — r^ 

i \ok\ 

D IciRc 
! 1| ; \Y 

\ i\ lis 



[{jfrjKynf} 



Fig. 166. — Expanding the hub. 

the hole in the ram, it is more economical to use a bushing A, as 
shown in Fig. 164, thereby avoiding the use of steel of large 
diameter for the punches. The die-holder G has a threaded 
bushing E to seat the die and at the same time retain the stripper 
F, which is sectionally held together by a wire spring H to allow 
the necessary expansion when the shell is pushed through it. 
It then closes around the punch and strips the shell when the 
punch is withdrawn. 

The fourth operation is done on a double-end trimming 
lathe; in it the shell is trimmed to 3% in. in length. 



The Fifth Operation 

In the fifth operation the shell is expanded at G, with the aid 
of lard oil, in the die and punch shown in Fig. 166. The dies C 



DRAWING SHEET METAL 107 

are made in halves and are set in the heavy cast-iron holder D, 
being held solid by the screw E and the handle F. The spacing 
block B is removed instantly when the screw pressure is re- 
leased. This saves time which would otherwise be taken up in 
turning the screw far enough back to allow the hub to be put in 
place and removed. 

The dies and punches are highly polished. The punch A 
is ground a close fit for the lj^-in. hole in the die, so as not to 
let the oil escape when the punch descends. The die is kept 
overflowing with oil by an automatic pump. The punch A is 
adjusted so it will enter the die about 1}4 m -> thereby giving the 
desired result. 

It will be noticed that the hub at A is stretched and thinned 
out more than at any other point. This is desirable and makes 
it easier for the sixth-operation die to give it the proper shape. 

Sixth Operation 

The sixth-operation die and punch, shown in Fig. 167, is a 
toggle die and punch that does a neat and satisfactory job. It 
is necessary that the iiub be held to an accurate diameter on the 
inside, as each end eventually will retain a ball-bearing cup 
pressed into place. 

The. bar A is connected to the dies G and J by the links B, 
which force the. plungers C against the die D. The plugs F 
in the plungers size the inside of the hub and at the same time 
act as guides. 

The die D is in halves and is opened to insert or remove 
work by turning the screw E. Cams have been used in place of 
the screw, but the screw works better. 

The lower end of the front half of the die D is seated at H 
and is free to work back and forth the necessary distance to 
replace the finished hub. Two tapped holes / are to fasten 
the dies to the press. The gibs K are to hold the plungers C 
and at the same time allow them the necessary sliding freedom. 

Seventh Operation 

The seventh operation shown in Fig. 168 is also done with 
a toggle die and punch which operates similarly to the one 
for the sixth operation. It pierces sixteen holes %4 m - diame- 
ter in each flange. 



108 



PRACTICAL DIE-MAKING 



At A are shown the dies held in place by screws. Each 
die is in two parts to allow the hub to be placed in and removed 
from the die when finished. It is opened and closed by the 
screw C and the handle G. 

The perforating punches D are held by plates fastened by 
screws. The punches are made as short as possible to lessen 




Fig. 167. 




Fig. 168. 
Figs. 167 and 168. — Upsetting and perforating the flanges. 



the risk of bending and breaking. They should be oiled fre- 
quently with a little lard oil, which insures longer life and better 
results. At B is shown the clearance slot that is necessary to 
remove the piercing scrap. 

The first, second, third and fifth operations give better re- 
sults when performed in draw presses not running too fast, while 



DRAWING SHEET METAL 109 

the sixth- and seventh-operation dies and punches can be used 
in ordinary quick-acting presses. 

Hollow Balls from Flat Stock. — It was required to make a lot 
of hollow balls as shown at D, Fig. 169. The diameter was to 
be }4 i n - They were to be of sheet brass of sufficient thickness to 
withstand the stress of closing-in without collapsing. It is im- 
portant that the right thickness of metal be used, for if the 
stock be too thin it will collapse when being closed-in at the last 
two operations, and if the metal is too thick the closing-in 
operation will be rather difficult; there will be unnecessary wear 
on the punches and dies, and also a waste of stock. 

By experimenting it was found that the size which gave the 
best results was No. 20 B.w.g. or 0.035 in. for %-in. balls. 




Fig. 169. — Making hollow balls from flat stock. 
Table of Thickness op Stock for Balls of GrvEN Diameter 



iameter of ball 


Thickness of stock 


Diameter of ball 


Thickness of stock 


H 


0.010 


M 


0.035 


He 


0.014 


% 


0.042 


H 


0.018 


H 


0.049 


5 Ae 


0.022 


% 


0.058 


% 


0.025 


l 


0.062 


Ke 


0.032 







The Punch and Die 

In Fig. 170 is shown the punch and die for blanking and 
drawing into the cup, shown at A, Fig. 169. A feature of this 
die to which I would like to direct special attention is the stop 
A, Fig. 170. This style of stop, which is simple, differs from the 
common type, familiar to most tool makers, in that it has a 
movement in a horizontal as well as in a vertical direction. 
This is attained by making the finger a rather loose fit on the 
pin B and filling the edges around the hole to allow the finger 



110 PRACTICAL DIE-MAKING 

to move in a horizontal direction through a Small arc. The 
slot in the stripper into which the finger is fitted is milled about 
}£ 2 m - larger at the end nearest the center of the die, showing 
so much play for the finger. 

The spring C holds the working end of the finger pressed down 
by the die and also pressed against the direction of the feed, so 
that when the stock is fed against it the finger is forced back to 
3^$2 m - against the back of the slot and is brought to a positive 
stop. Then when the punch is nearing the end of its stroke 
the adjustable rod D comes down on the board end of the finger, 
causing the working end to rise clear of the stock, when the 
spring forces it back to the forward side of the slot, where it 
remains until the stock is fed in for another stroke. The finger 
will then drop into the hole which has just been punched in 
the scrap, and the same operation is performed as before. 

The blank is punched out of 1^-in. wide stock and drawn 
up as shown. The cup is lifted out in the upper die, clear of 
the stripper, when it is ejected by the knockout E and falls 
into the receptacle at the rear of the press, which should be 
inclined at about 45 degrees. 

The Second Drawing 

In Fig. 171 are shown the punch and die for the second draw- 
ing, and the result is shown at B, Fig. 169, and in detail in Fig. 
171. It will be observed from the detail that the cup is 0.050 in. 
smaller in diameter than the finished ball. The reason for this 
is to allow for "bulging" when the ball is being closed-in in the 
following operation. The punch and die for the first closing-in 
are shown at Fig. 172, and the piece after this operation is 
shown at C, Fig. 169, and also in detail in Fig. 172. 

In Fig. 173 are shown the punch and die for the last opera- 
tion, which completes the ball as required in this case. If it 
were required to bring the ball down to a greater degree of re- 
finement than is possible on a press, then it would have to be 
rolled between disks in the same manner as ball bearings, when 
the opening shown in the ball at D, Fig. 169, would be entirely 
closed and the ball would be brought down to within 0.001 in. 
of correct diameter as well as sphericitj^. 

This latter method has been used in the manufacturing of 
gold beads and other novelties, such as hatpin heads and the 



DRAWING SHEET METAL 



111 



like. If it is required to manufacture a solid gold bead an eco- 
nomical way is to make the head out of sheet copper plated to 
whatever thickness of gold we desire to put into the bead. The 
copper plate should be strong enough to stand up under the 




Figs. 170 to 173. 



Fig. 170. 
-Tools for making hollow balls. 



stress of closing-in. The ball is then drawn up in the manner 
described, with the gold on the outside of the ball. The copper 
is then dissolved in a solution of 1 part muriatic and 11 parts 
sulphuric acid, leaving the thin wall of solid gold. 



112 



PR A C TICAL DIE-MA KING 



Method of Making Door Knobs.— In Fig. 174 is shown a very 
economical combination die for such work as making sheet- 
metal door knobs. This is what is known as a regular com- 
bination die and is made as follows : The base A is of cast iron 
and forms the center of the drawing die B. Above is the knock- 



,-i — i, 




Figs. 174 to 177.- 



Fig. 176. 
-Combination die for door knobs. 



out pad C; this does not have to conform to the shape of the 
shell, for the drawing alone insures the metal being formed around 
the cast-iron center B. The draw ring D is forced up by heavy 
rubbers which act on the four pins E. The cutting edge F 
is inserted in the lower cast-iron die-holder and held by screws. 



DRAWING SHEET METAL 113 

The punch G is made of one piece of tool steel properly hardened 
and ground, as shown. 

After it leaves the combination die, the shell is trimmed 
on the outer edge to the height indicated in Fig. 175. It is 
then placed in the lower die, Fig. 176, but before putting the 
shell in place the brass center piece of the knob H is put in the 
die.. The punch then descends and forms the shell around the 
curved shape, forcing the metal, or shell, into the groove in the 
brass center H. On the return stroke of the press the knock- 
out pin / lifts the combined shell and center out of the die, com- 
pleting the operation, as shown in Fig. 177. 

In the closing die, the punch J is made of one piece of steel 
and fits the combination die K, so that when this punch comes 
into contact with the bottom of the shell it will not distort it 
in any way during the rest of the operation. The die K is made 
of tool steel worked out to the shape of the cast-brass center H, 
and also the shape of the ball, or knob. 

Deep Drawing of Metals. — The drawing of metals, as the deep 
forming of cup- or shell-shaped hollow bodies is erroneously 
called in the shop language, because as generally practised the 
operation is one of pressing or pushing rather than drawing a 
desired form, is still a mystery to a large number of metal 
workers. 

The advance and rapid improvements in the making of cold- 
rolled strip steel and the phenomenal increase in its uses have 
opened an almost unlimited field of usefulness for the material. 

The most important part of the forming operations on deep 
hollow bodies consists in holding the flange flat and preventing 
it from crimping. Drawing dies, in their main parts, consist: 

1. Of one or several punches, if more than one forming opera- 
tion is required to give the body the desired depth and shape, 
which is generally the case; each following punch is a step nearer 
to the final shape and inside dimensions of the piece than the 
preceding one. 

2. Of a ring, frame or hollow block, the die, into which the 
metal is pushed. There may be also one or several required to 
finish the piece, according to the depth or difficulty of its shape, 
but in many cases several punches can be used in connection with 
the same die, inasmuch as it is the punches which give the shape 
to the piece and it is not absolutely essential that the shapes of 
the dies should correspond to those of the punches, although in 



114 PRACTICAL DIE-MAKING 

many cases it is beneficial that they should because they help 
to straighten out and stiffen the formed cup. 

3. Of a so-called drawing ring, which is in most cases a flat 
plate or frame with a hole in it of the approximate largest diame- 
ter of the piece. This drawing ring is fastened cither to the 
stripper slide of the press, if a double-acting drawing press is 
used, or is fastened to the die shoe or punch-holder in such a way 
that a rubber or spring buffer applies a stiff pressure against it. 

The purpose of this drawing ring is to keep the rim or flange of 
the blank flat and prevent it from crimping. The pressure of 
the buffer must be regulated to allow the blank to slide with the 
downward motion of the punch, but be at the same time stiff 
enough to prevent the formation of wrinkles around the flange 
of the blank. The surfaces of the die and drawing ring must be 
parallel and smooth and should be well lubricated with a thick 
oil or drawing compound to make them slippery. The pressure 
of the drawing ring must be uniform to allow the stock to slide 
in equally from all directions. The upper edge of the die should 
be well rounded and sharp corners, which tend to lock the metal, 
should be avoided or at least, if the finished product requires 
them, the forming of these should be delayed to the last operation 
when the desired depth of the body has been reached. 

While these general notes apply to all deep drawing operations 
on semi-spherical, cylindrical, cone- or cup-shaped hollow bodies 
and the cited difficulties are common to all of these, still they are 
easy in comparison with forming cubic, prismatic or polygonal 
shapes because the absence of corners in the former shapes gives 
the metal a more equal resistance and the formation of wrinkles 
at the flange is uniformly on radial lines toward the center 
of the blank and can therefore be taken care of more easily than 
in the later case, where the crimping takes place in the corners 
only. The stock which does flow over the straight edges of the 
die does not get its due share of concentration and the surplus 
stock is crowded together in the corners and as it cannot either 
condense or stretch there fast enough, because locked on all sides 
by the straight flanges, it hardens quickly, and the result is that 
the material tears. The. sharper and fewer the corners, the more 
readily the stock will break there, a three-cornered cup will 
therefore form harder and break quicker at the corners than a 
four- or a six-cornered one. 

The three samples shown in Fig. 178 are evidence of the tend- 



DRAWING SHEET METAL 115 




Fig. 178. — How steel tears in drawing. 




Fig. 179. — Four samples of drawing. 




Fig. 180. — Difficult deep drawing. 




Fig. 181. — Cases of bronze. 



116 PRACTICAL DIE-MAKING 

ency of steel to tear on the grain. In each case, the dies had to 
be altered to less acute angles where the stock broke and the final 
shapes were brought out in the succeeding operations, after 
sufficient material had been pressed to the full depth. 

Four samples of comparatively simple pressed parts, of cylin- 
drical or cup shape, are shown in Fig. 179. The material 
is "deep-drawing" cold-rolled strip steel of the same grade 
and temper as used for the work in Fig. 178. These pieces were 
pressed in from one to four operations. Fine threads lj-fc X 40 
in. were cut in B and D with a collapsing tap without previous 
boring on a screw machine at 128 ft. surface speed per minute; 
the threads were perfect and not torn. 

Two samples of difficult deep-press work are shown in Fig. 180. 
These polygonal cups have many irregular and dangerous corners, 
which made it difficult to lay out the blanks, and the corners lock 
the material, which is 0.032-in. "deep-drawing" cold-rolled steel. 

The cylindrical and rectangular cases shown in Fig. 181 were 
made of 0.04-in. bronze metal and are, on account of their large 
size, not difficult to press. 

To resume, there are six cardinal points to be considered in 
order to obtain satisfactory results in forming hollow bodies, 
viz.: 

1. Soft, ductile, uniform metal. 

2. A properly constructed set of punches and dies, enabling 
the material to flow, rather than to be stretched or drawn into 
the desired shape. 

3. Avoidance of sharp corners or edges when possible. 

4. Properly adjusted drawing rings to keep the flanges from 
crimping. 

5. A slow-acting press, preferably of the toggle type. 

6. A correctly proportioned blank, the dimensions of which 
are either found by the "cut-and-try" method, or by weighing 
the model and calculating therefrom the size of the blank or 
by the more scientific and reliable graphical method, by laying out 
the blank on the drawing board. 

Drawing Brass Shells and Other Press Work. — Little infor- 
mation is usually available as to the actual working methods used 
in drawing shells from brass, copper and steel. 

Brass is rolled in several grades or tempers, such as dead-soft, 
soft, quarter-hard, half-hard, hard and high-hard. Hard and 
high-hard brass cannot be drawn without first being annealed; 



' DRAWING SHEET METAL 117 

half-hard and quarter-hard can be bent or formed in snarp angles 
and in some cases drawn in shallow shells, but for deep-drawn 
shells such as cartridges, a soft brass must be used to start with 
and then be annealed between operations. Some do much more 
annealing than is necessary because they are not equipped with 
the proper tools and machines to do the work. To gain the maxi- 
mum efficiency one must equip with the best apparatus on the 
market for the work, this being often paid for out of the first 
month's production. 

To save operations the larger shells can be blanked and drawn 
part way in qne operation, or if a double-drawing press, such as 
the Bliss, is used they can be blanked and the first and second 
draw also done in one operation. Again, small shells can be 
blanked and cupped four or six at a time with " push-through " 
dies on a cam press. In the case of the Bliss toggle-action double- 
drawing press, the shell is blanked and cupped on the upper dies 
(which are push-through dies) and is then dropped into the lower 
dies and receives the second draw while the metal is still warm 
from the first draw, thus saving the annealing. 

Production Rates on Small Shells 

With a double-action cam press the smaller shells can be cut 
and drawn from the strip with push-through dies, four at a time, 
at the rate of 150 to 200 shells per minute; and can, after anneal- 
ing, be reduced on the double-action cam reducing press at the 
rate 6f about 80 per minute. 

Clean lard oil of good quality is one of the best lubricants for 
brass, but if the brass receives too much heat in the annealing, 
the shell often cracks along the sides or breaks out entirely at 
the bottom. In annealing, care should be taken not to get the 
shells too hot; a dull cherry-red is about right, and the work 
should be allowed to cool by itself if the best results are to be 
obtained. If the work must be cooled more quickly, use warm 
water. Much work is ruined by heating the shells too hot and 
then immersing them in cold running water. 

For a shell drawn from light thin brass, a very effective lubri- 
cant is made by using one part of hard soap dissolved in one part 
by measure of warm water and one part of clean lard oil. The 
work cannot stand long in this state after being drawn, as the 
alkali in the soap will corrode the brass. 



118 PRACTICAL DIE-MAKING 

Clean lard oil is mentioned because it seems best to call atten- 
tion to a practice in some shops of saving the oil that has been used 
on screw machines and sending it to the pressroom to be used on 
the dies. This oil is all right for cutting, but is very poor for 
drawing, as it is often filled with small particles of steel that do 
grave harm to the drawing tool. The practice is bad, as a tiny 
particle of steel will cling to the dies and more will collect until 
soon there is enough to scratch the work. The scratching of the 
sides of the shells should be watched for all the time by the 
operator, especially on work which is drawn two or three times. 
If the shell is scratched in the first draw, after it is annealed and 
drawn the second time the scratch will be enlarged or will some- 
times break through the metal entirely and spoil the work. 

Importance of Clean Lubricant 

The radius on a drawing tool should at all times be kept per- 
fectly smooth. When it becomes rough or scratched from con- 
stant use, it should be stoned off with a fine stone and then 
polished with finest emery or crocus cloth. The operator should 
watch this and also the oil or other lubricant that he is using and 
see that they are kept free from dirt and sediment. 

After stoning the dies care must be taken to see that no small 
particles of the stone are left embedded in them. They should 
be washed off with gasoline. Sometimes the metal will flake 
off and cling to the dies, but this will not take place if plenty of 
the lubricant is kept on the work. If it should take place in 
spite of this, it is evident that the metal is too soft and shows that 
it can be drawn without annealing. 

Copper shells are drawn in much the same way and the same 
conditions apply as in drawing bras,s shells. A very soft copper 
is used to start with and is annealed between operations the same 
as with brass. As for lubricants, lard oil can be used, but very 
good success is obtained with soap, oil and warm water. Drawn 
copper shells are little used except in electrical work and as a base- 
metal for silverware for the reason that copper is so much more 
expensive than brass. 

The Problem of the Steel Shell 

Steel shells often present very difficult problems, which can 
only be solved by experiment ; but a few suggestions can be given 



DRAWING SHEET METAL 119 

which may be of some help. Lard oil is successfully used as a 
lubricant on cold-rolled steel and also when deep-drawing steel 
up to 0.020 in. thick, but for steel over that gage a great variety 
of materials as lubricants are used. 

In one case it seemed almost impossible to get an oil or other 
lubricant heavy enough to keep the shell from scratching and the 
metal from flaking off on the dies. This was a shell drawn from 
cold-rolled steel 0.0625 in. thick. As a last resort dry white lead, 
mixed with machine oil to a thickness similar to heavy paint, 
was tried with marked success. The principle involved in this 
case was to furnish a lubricant heavy enough to produce a light 
film that would maintain itself between the metal and the die. 
While this mixture was a success as a lubricant, it was difficult to 
remove the lead from finished work. It could not be dissolved 
in any acid dip and could only be removed by washing each piece 
separately in gasoline. White French zinc ground in oil, mixed 
with the machine oil was then tried. This did excellent work, 
but was too expensive. 

Successful Lubricant for Drawing Steel 

At last an exceptionally good lubricant was found for both 
cold-rolled and deep-drawing steel, which was both cheap and 
easy to dissolve in a dip or to clean off. It is composed of machine 
oil and precipitated chalk. It is used only on metal over 0.030 
in. thick. 

In some cases where steel shells have to be drawn more than 
once they have to be annealed, and, in doing this, care must be 
taken not to get them too hot. They are brought to a nice bright 
red and then allowed to cool covered with air-slaked lime. This 
gives very good results, and 0,020-in. spring steel and 0.015-in. 
tool steel in shallow shells have been drawn by annealing in this 
way and then retempering afterward. 

The cardinal points in all drawing work are to keep the dies 
perfectly smooth and in good order and to use a good lubricant. 

Pressure Required to Draw Sheet Metal. — In view of the 
small amount of information available on the pressure required 
to draw sheet metal, a study of this work was made at the Frank- 
ford Arsenal at Philadelphia, Pa. These data deal with the 
drawing of cartridge cases for projectiles or fixed ammunition. 

In the language of the ammunition department the term "pro- 



120 



PRACTICAL DIE-MAKING 







DRAWING SHEET METAL 121 

jectile" refers to the complete ammunition ready to be placed 
in the gun, the "case" contains the powder and also holds the 
"shell" in the outer end. These terms will be used throughout 
the article. 

Beginning with the ammunition for the new Springfield rifles, 
which have replaced the Krags and which have a bore of 0.3 in., 
we have the various operations as shown in Fig. 182. 

At first a sheet of cartridge brass No. 12 gage, or 0.0808 in. is 
fed from the strip under a punch through a press carrying four 
punches. This blanks out four cases at each stroke and cups 
them by inside plungers operated by the double-acting ram. 
These blanks are 1}{q in. diameter before cupping, the outer 
diameter of the cup being % in. and the depth about }4 m - This 
press runs at 102 r.p.m. and requires 15 hp. to drive it with the 
four punches. This means 408 cups per minute. The cup is 
shown at A, Fig. 182. 

Lard oil has been found the best lubricant for this operation, 
although the further drawing of the cases is done with what is 
known as Lovewell compound. 

Five Drawing Operations 

There are five drawing operations to take the shell to the full 
length and to the proper thickness. The first drawing B in- 
creases the length about %q in. and only two shells are drawn 
at once. These are drawn at the rate of 92 strokes per minute, 
or 184 cases, 2% hp. being required for this operation. 

The next two draws, C and D, are performed four at once at 
the same speed as No. 1, making 368 pieces per minute with 7 
hp. The second draw increases the length about }^ in., while in 
the third draw the length increases from 3^ to % in., with corre- 
sponding extensions on the other two operations. 

The fourth and fifth operations E and F complete the case as 
far as length is concerned and are done two at each stroke, at the 
same rate, 92 per minute. The fourth operation adds a little 
over }4 m - to the case, while the fifth makes it % in. more, or a 
total length of 2% in. on the low side. The third and fourth 
operations require Z x /i hp. each at the rate of output named. 

These cases are annealed between each operation. 

The other operations are : Trimming as at G, heading and pre- 
paring for the primer, reducing the end to receive the shell, 



122 PRACTICAL DIE-MAKING 

turning under the head, and so on to the finished cartridge, as 
seen at H. 

Another example of press work which is of interest is the making 
of the jackets for the shell, which are of cupro-nickel. These 
blanks are J-g in. diameter and 0.023 in. thick. They are punched 
and drawn five at a stroke at 102 strokes per minute, making an 
output of 510 jackets per minute from one machine which re- 
quires 6% hp. The thickness on the metal is reduced from 0.023 
to 0.018 in. by this operation. 

Drawing Larger Shells 

The case for the one-pounder, which means the field gun, in 
which the projectile weighs 1 lb., begins as a disk 2.85 in. diameter, 
0.205 in. thick and weighs 63^ oz. When finished it measures 
5.65 in. long and has an inside diameter of 1.457 in. with walls 
0.04 in. thick. 

The blanks are first cut about % in. deep and five operations 
are required to draw them to their full length. They are an- 
nealed, pickled and washed between each operation, the pickling 
being to remove the scale formed by annealing; an oil of vitriol 
pickle is used. This makes the drawing operations easier on the 
dies. Different compounds are used, among them the Acme and 
the New Era. It is understood that both of these have oil as 
one of the ingredients. These are drawn in small hydraulic 
presses at the rate of about 10 per minute for each draw, and 
require 1 ton pressure. 

Cases for the 3-in. Projectiles 

The cases for the 3-in. field guns start as disks 5.805 in. di- 
ameter and 0.313 in. thick, the blank weighing 2.544 lb. When 
finished they are 10.8 in. long with walls 0.04 in. thick. The disk 
is first cupped and then requires five drawing operations; the last 
drawbeing about 5 in. in length. 

In the drawing of these cases the metal at the bottom remains 
at practically the thickness of the blank used, until the heading 
operation. The bottom remains in the form of a rounded or 
cupped end, until the heading operation flattens out and expands 
a portion of the metal in the head to form a rim for holding the 
case in the gun and giving a grip for the ejector. The change of 
form which takes place is indicated in Fig. 183. 



DRAWING SHEET METAL 123 

In the case of the 3-in. cases the metal is forced out from % 6 
to 34 m- each side of the body, or the diameter is increased from 
% to yi, in. This also thins the head and leaves it perfectly 
flat, ready to be bored for the primer. The heading operation 
in this case requires a pressure of 625 tons. It is done on a single 
machine which is equipped with two sets of dies, so that one can 
be loading while the other is operating on a case. In this way 
500 cases a day are headed up, which is at the rate of 62^ per 
hour in the eight-hour day. 

Another somewhat similar example is the 3-in. case for the 
15-pounder, in which the disk or blank is 9.38 in. diameter by 
0.438 in. thick and weighs 934 lb. The cupping operation re- 
quires 120 tons pressure and there are eight drawing operations 
in addition to this. These draw the case to a total length of 2734 
in. with the outside diameter 334 m - 

The whole case is then tapered the entire length in two opera- 
tions until the diameter has been reduced from 334 to 2.97 in. 
and the point swaged down an inch in diameter and for a space 
of about 43^ in. to hold the projectile. These two operations 
require 150 tons each. The cases are annealed between each 
operation to about 1200°F., the output being 400 per day. The 
heading operation on this side case takes a pressure of 750 tons. 

A Laeger Field Gun 

On the case for the 4.72 field gun the blank is 9.3 in. diameter, 
0.754 in. thick and weighs 15 lb. 7 oz. This is cupped and has 
nine drawing operations. The cupping pressure is 124 tons and 
this pressure gradually reduces to the last operation, which re- 
quires about 25 tons and increases the length about 10 in. 

The heading increases the diameter about ^{q in. on each 
side or about % in. total, and takes 1500 tons pressure. This is 
done at the rate of about 10 per hour, counting the total handling 
in the machine. 

In the 6-in. shell for the Armstrong gun, the blanks are left 
11.6 in. diameter, 0.77 in. thick and weigh 25 lb. each. The 
first operation cups them about 3 in. deep and 13 further opera- 
tions are required to secure the desired length of 24 in. The 
finished thickness is about 0.05 in. on the walls and about 0.5 
in. on the head. The cupping pressure is 150 tons. There are 
nine drawing operations. The required pressure drops from 



124 PRACTICAL DIE-MAKING 

10 to 15 tons with each successive draw, requiring about 25 tons 
for the last draw, which increases the length about 9 in. 

The heading operation requires 1800 tons and about 90 cases 
in eight hours is a good average output. 

The 6-in. howitzer case is practically the same diameter as 
the other, but is only 1034 in. long when finished. For this 
reason it requires a blank only 9.68 in. diameter, the thickness 
being 0.5 in. and the weight 9 lb. This has seven drawing 
operations in addition to the cupping, 110 tons being required 
for the first operation, this decreases until 25 tons suffices for 
the last draw. The finished thickness of the walls is about 0.04 
in., and the output from 90 to 100 per day. The heading is 
practically the same as in the 6-in. Armstrong case. 

Dies for a Drawn Copper Shell. — The problem of making 
tools for manufacturing copper ferrules with only one drawing 
and without annealing, was solved in the manner shown in Figs. 
184 to 191. These ferrules were for a cartridge fuse the inside 
dimensions being, diameter 1}^ in.; length 134 in.; thickness of 
stock 3^6 m - with the ends flat and the sides parallel for electrical 
contact. Only one drawing, one flattening and one trimming 
operation was necessary. 

Many considered that it was impossible to draw to this depth 
in one operation as the usual procedure is to make the first shell 
larger in diameter and shallow, closing it in by reducing dies 
after the various annealings. Then it would have to be trimmed 
and the end flattened and sized. Usual methods were discarded, 
the first problem being to find the right diameter of the blank, 
and do more or less experimenting. 

Instead of following the usual calculations we cut a blank 
that was obviously too large' and placed it between two pieces 
of cold rolled steel as in Fig. 184. These plates were % m - thick 
and clamped together with screws so that the tension on the 
blank to be drawn might be regulated to suit. 

The hole in the lower plate B represents the outside diameter 
of the ferrule and the hole in the upper plate C, the inside diame- 
ter of the ferrule. This also acts as a guide for the punch. The 
end of the punch was left square in the experiment first to see 
just how deep a draw could be made before fracture occurred. 
Previous experience had shown that it was impossible to draw 
Y\ 6-in. copper to any great depth and retain a square bottom, 
so that the first result of a cup nearly % in. deep, was encour- 



■DRAWING SHEET METAL 



125 



aging enough to make a second trial. In this the shape of the 
opening in the bottom plate was changed as shown in Fig. 185. 
This shape lessens the resistance of the metal to drawing owing 
to the increase in the angle of the opening, the idea being to give 
the blank the shape of a disk before pushing it through the 
die. This result was very good when it is considered that a 
square-bottomed punch was used, but the fracture would occur 
at the bottom when the metal crowded in too much at the top. 

Finding Possible Depth of Draw 

The next step was to make the end (5f the punch round as 
shown in Fig. 185 and another blank tried to see if the one draw 
plan would work out in practice. This gave a shell without a 
fracture and after several trials the punch shape shown in the 
dotted outline in Fig. 185 was found to be best suited for 
this work. These experiments were made in an arbor press 
and, having proved that the draw could be made in one 



wmm win 



Fig. 184. Fig. 185. 

Figs. 184 and 185. — Dies for drawing shells in one die. 



operation, the work was put on the power press and further in- 
formation secured as to the speed which could be maintained. 
This showed that thirty-five strokes per minute was the fastest 
which could be used satisfactorily, although speeds as high as 
sixty strokes per minute were tried. At the higher speed every 
shell would fracture but thirty-five strokes gave entire satisfaction. 
Sufficient data having been obtained during the experimental 
drawings both as to the size of the blank and the kind of press to 
use, the work was put on a press of the single-acting type. Ex- 
periments were also made with the plates producing an even 
tension on the blank during the drawing operation while the 
punch draws the shell, giving the same conditions as exist in a 
double-acting press. 



126 PRACTICAL DIE-MAKING 

Uniform Prfssure on the Blank 

In designing the die attention was paid to the fact that with a 
single-acting cut and draw die, the tension on the pressure ring 
increases as the cutting punch descends in the die, which has a 
tendency to stretch the metal. With heavy stock and a deep 
draw as in this case, fracture of the sides of the cup would be 
sure to result. It therefore became necessary to so design this 
die as to keep an even pressure on the drawing ring and the 
die was made as illustrated in Figs. 186 and 187, in which A is 
the cutting and drawing punch and B the knockout. The plate 
C is fastened to this "punch and has the controlling pins D,D 
screwed into it. These are adjustable to obtain the proper 
relation to the contacts pins E,E, these being fastened to the 
buffer plate F. There is a cutting die G and a pressure ring 
H which slides on the drawing plug I. 

The pins K,K support the pressure ring and are fastened to 
the sliding bushing L, which in turn connects with the plate F. 
This construction conforms with the ordinary dies of this type, 
the details being shown in the plan view and cross-section. 
The cutting die and drawing plug are fastened to the plate M. 

The bolster plate N is drilled to receive the contact pins E,E, 
which must operate freely. The buffer rod is shown at P, the 
washer at T, and the adjusting nut at S. It will be noted that 
the angle on the cutting punch and the pressure ring is the same 
as in the experimental plate in Fig. 185 and also that the plug I 
is shaped like the experimental punch. 

Dishing the Blank 

As the cutting punch enters the die, the blank, before being 
drawn over the plug, is dished to the required angle. The con- 
trolling pins are adjusted so as to allow as little pressure as 
possible, this pressure remaining the same throughout the draw. 
By this arrangement a single-acting drawing die is made to act 
on a double-acting principle. It also has the advantage of being 
able to dish the blank, which would be hard to do in a double- 
acting die. 

Squaring the Bottom 

The next operation is to flatten the end, this being one of the 
requirements of the job. The flattening die is shown in Figs. 



DRAWING SHEET METAL 



127 





Fig. 187 
Figs. 186 and 187. — Dies used for drawing shell. 



128 



PRACTICAL DIE-MAKING 



188 and 189, and is so simple as to need no explanation. The 
flattening punch is shown at A, the knockout at B, the die at C 
and the bolster at E. During the flattening operation a small 
bulge appeared at F as shown in the dotted outline, but this 
was of no consequence as this defect was remedied in the next 
operation. 

In the first operation the shell was drawn only deep enough to 
leave a bell mouth at G (see outline, Fig. 189), to give the results 
necessary in the third and last operation, namely, sizing and 
trimming, shown in Figs. 190 and 191. 






BlL B 




Jill 


A 


urn minium 


i 





Fig. 188 




Fig. 189. 
Figs. 188 and 189. — Dies for squaring the bottom. 

The shell is drawn about 0.005 in. larger in diameter in the 
first operation to allow for sizing or ironing out the sides in the 
sizing die. This die is made as nearly accurate to size as possible 
and is highly polished to avoid scratching and galling. 

Trimming to Length 

The principle used in trimming is somewhat different from the 
ordinary trimming die where the shell after trimming would have 
a similar appearance to the dotted outline of the shell shown in 
Fig. 189, only not so pronounced, after which it would be pushed 
through a die in order to close the end. In this case the mel al is 
cut while forcing the shell through the die, being forced against 
the cutting edge. of the punch. 

Referring to Figs. 190 and 191, A is the punch holder, and B, 



DRAWING SHEET METAL 



129 



the cutting or trimming punch, is made to the exact size to fit 
the die G. The pilot C is turned the same diameter as the inside 
of the shell, the shoulder of the pilot clamping the cutting 
punch fast to the holder by means of the nut E. The scrap 
cutting punches are shown at D. 




Figs. 190 and 191.- 



Fig. 191. 

-Punch holder and trimming punch. 



The die G is equipped with sliding gages F,F, which open as 
the shell passes through. These gages are beveled on the 
sides and held in position by the guides K, which are screwed 
fast to the die. The gages F,F are actuated by the springs 
nesting in the posts 1,1, these being fastened to the bolster H. 

The die being of the required diameter and the shell slightly 



130 PRACTICAL DIE-MAKING 

larger, the action is that of burnishing, leaving a smooth shell, 
stretching it very slightly. 

The punch being smaller enters the shell easily and straightens 
it up as it starts to go through the die. The stripping is done 
at the shoulder of the die L. 

Copper being of a soft nature, especially drawing copper, it is 
necessary to have a good fit between the die and punch B to 
avoid a burr. If it is correct, thousands can be trimmed before 
the sharpening of the face becomes necessary. 

Excellent results in trimming steel products of odd shapes 
have also been obtained by this method. 

Drawing 18-lb. Cartridge Cases on Bulldozers and Frog 
Planers. — The exigencies of war often bring out unheard of 
methods and devices. The Canadian-Pacific's Angus shops 
turned out thousands of cartridge cases, using such apparently un- 
suitable machines as bulldozers, for every press operation except 
heading and indenting, and they not only secured a high- 
grade product, but the ultimate capacity of 3000 cases per day. 
Moreover, there was not one man employed on this work who 
had previously worked in a brass-drawing shop or had experience 
of a similar nature. 

A truck-shop building was cleaned out and made over into the 
cartridge department. As a bit of dust or grit on one of the 
drawing dies or plungers makes an ugly scratch in the case, and 
it was considered more advisable to keep this shop free from 
smoke and dust than to try to avoid transportation. Therefore, 
as the nearest available building for the annealing furnaces was 
the blacksmith shop across the midway, this shop was used for 
the drawing operations, and the indenting and heading presses 
were also installed there. 

List of Operations 

The operations as performed on cartridge cases at the Angus 
shops were as follows: 

1. Blank 10. Anneal 19. Second trim 

2. Cup 11. Third draw 20. Head 

3. Anneal 12. Anneal 21. Semi-anneal 

4. First draw 13. Fourth draw 22. First taper 

5. Anneal 14. Anneal 23. Second taper 

6. Second draw 15. Fifth draw 24. Head turning 

7. First indent 16. First trim 25. Parallel cutting 

8. Anneal 17. Anneal 26. St ami) 

9. Second indent 18. Sixth draw 27. Shop inspection 



DRAWING SHEET METAL 



131 





C 



o 





132 



PRACTICAL DIE-MAKING 



There were six drawing and seven annealing operations; the 
cupping and first four draws being handled on bulldozers, and 
the last two draws, on frog planers. The round blank is punched 
out of strips of sheet brass, and each disk weighs 3 lb. 9)^ oz. at 
the start. By the time it has become a finished case, it has lost 
l/-f lb. due to trimming, the finished weight being 2.49 lb. 

All stages in the process are represented in Fig. 192. The 
round, flat blank punched out of strip brass is shown at A ; the 
cup made directly from this is shown at B, and C and D repre- 



0.300 




1 1 1 1 
TEST ON ROLLED BRASS DISK 








/ 


0.250 
0.200 
0.150 
Q.I00 

0.050 

o 




D= Original Diameter 
P= 13,000 D™+320DI 














FOR CARTRIDGES 
D--!74D 28 =I4.S 














1=40 

P=33 




5 Jons 




uy 




y 












































J 10 20 JO 40 50 60 70 80 90 100 




lV.sk 


20 40 60 60 100 120 140 160 160 200 
£"Disk 




load in Thousands of Pounds 




Fk 


i. 193 


.—Re 


suit c 


f exp 


jrimei 


its in 


draw 


ng- 





sent the first and second draws respectively. The indented 
case is shown at E, the indenting being performed after the second 
draw. The third, fourth, fifth and sixth draws are shown at 
F, G, H and I. At J is the headed cartridge case, while K repre- 
sents the completely tapered case with its base machined and 
ready for the primer, which, of course, is not furnished at this 
shop nor attached until the complete cartridge is in government 
hands. 

Motor-driven Machines 



The bulldozers and planers are all motor driven. There 
are four of each of these machines, one of the bulldozers being 
provided with three sets of plungers and dies and the others 
having but one set each. On the bulldozers, the die is mounted 



DRAWING SHEET METAL 133 

on a special crosshead, and the plunger, on the rail. On the 
planers, the punch is mounted on the rail, and the die-holder, 
on an angle-block on the table. 

Little was known at the start about the pressures required 
to accomplish the various drawing and heading operations. To 
throw light on this subject, experiments were made with brass 
disks of the same composition as the cartridge cases, the effect 
of pressure upon them being studied. The results of these 
experiments are shown in Fig. 193, and they served as the 
basis for calculations when the presses were built. 

The evolution of the punches and dies for this work was 
a matter of much labor on the part of the toolroom foreman, 
W. H. Whitehouse, and while Mr. Vaughn, of the Canadian 
Pacific was assured in his own mind of the practicability of 




Fig. 194. — Drawing cases in a bull-dozer. 

drawing such work on bulldozers, it was a. matter that had to be 
proved, no precedent being known for such novel use of a ma- 
chine of this type. The first set of plungers and dies were worked 
up to be tried on a single bulldozer. After experiments ex- 
tending over two weeks' time, successful cases were produced, 
and when the first three of these had been secured, the Canadian 
Shell Committee was notified of the feasibility of making car- 
tridge cases in this way. The entire committee was at hand 
within a day or two to witness the demonstration of bulldozers 
in their new role, and as a result, a large contract for cartridge 
cases was placed with the Angus shops. 



134 



PRACTICAL DIE-MAKING 




DRAWING SHEET METAL 135 

One of the bulldozers, a modern machine, has been equipped 
with three sets of plungers and dies. The center one takes care 
of the cupping of the disk, while the two outside ones handle the 
first draw. A recess is provided behind the plate D, Fig. 194, 
to hold the flat disk as the plunger advances. Plates of this 
kind are necessary only for the cupping operation, as for all of 
the succeeding draws the cup or shell is slipped over the plunger 
while it is in its withdrawn position. 

An ingenious method of discharging the pieces after each 
operation has been devised in the simple form of galvanized- 
iron conductor pipe, as shown at A, B and C in Fig. 194. These 
convey the pieces to the back of the machine, where they roll 
down a chute into boxes. As each case passes through the die, 

Contractor's Initials or %, ,,„„,"■ ^Ss 

recognized Trade Mark § \ nn?"p *~3 

Ft - tvtohw, H o.%5" f 




■\j< 



§~ Capacity 97 cubic inches £|£h 



5 7M I ~l4'Threads per inch ; 

I "OISS'E-A , n ; ? r<> L 

S^/j/m"^-^ 6 " _ : : — r— "- 



=^T £-=g= ±=^=fr ..« Taper 0.04066 per men on dimeter (^ 

Date of Manufacture H0.B7 ! H\\<- « ,, „ Parallel 



■H 0/6 LQIS __ H 11.60 

LIGHT SCREW PRESS 
CLEAN WITH SAND ON MANDRIL 

STAMPING 

Fig. 196.— Dimensions of 18-lb. shell. 

it pushes forward the ones ahead of it, causing them to climb 
the hills in the pipes. 

Frog planers were used for the last two draws for two reasons : 
first, they have a longer stroke than the bulldozers; second, they 
are more accurate. A special head was mounted on the planer 
cross-rail, from which the feed screws have been removed, and 
upon this the plunger holder was secured, the plunger fitting 
into it on a standard taper. The die was held upon a heavily 
ribbed cast-iron angle-block, the whole thing weighing some 
4 or 5 tons and serving not only to secure the die-holder, but 
also to prevent the table from rising. 

Good Reasoning Employed 

At first thought, the natural plan would apparently be to 
mount the die-holder upon the cross-rail and the plunger upon 



136 



PRACTICAL DIE-MAKING 



spy St j 93w iy Sjo H f, |< jfB >f»B|<- 




l< ^->U^/4-c^->-J 



DRAWING SHEET METAL 



137 



the angle-block. There was good reason for the opposite 
procedure, however, since any lift that occurs during the opera- 
tion will undoubtedly take place in the planer table and not 
in the cross-rail, which is a rigid member. The plunger, on ac- 
count of its long overhang, would be thrown out considerably 
by a few thousandths of an inch rise of the table; whereas the 
die, having a thickness of but 2 to 2% in., is not perceptibly 




B C 

Fig. 198. — -The heading punches. 



affected, as evidenced by the fact that the thickness of shell in 
these cartridge cases did not vary over Kooo m - 

In determining the suitability for a planer for the last two 
draws, a bulldozer cross-head was clamped upon a planer table 
and the punch was put upon the clapper block. After the 
feasibility of the machine was demonstrated, a cut was taken off 
of the table top and one side so that they indicated to Mooo m - 
The die- and punch-holder seats were then bored with a long 
bar lined up from the table and both holes finished at one setting. 




Indenting the shell. 



Four hundred cases are considered a "lot." To this, 10 per 
cent, is added as an allowance for loss. 

Full details of the shells in various stages are shown in Fig. 
195, these being secured from actual sections. All dimensions 
and tolerances are given in Fig. 196. All necessary details of 
the plunges and dies used are shown in Fig. 197. These dimen- 
sions are from actual practice and can be followed in any similar 
work. 



138 



PRACTICAL DIE-MAKING 



The heading punches are shown in Fig. 198 and those used for 
indenting, in 199. The details of the heading punch and com- 
posite dies appear in Fig. 200. 

? Groove for^ [*" V. 5 ? "^~ ;"" g>| 



Wire Handle 



rrmi" 





Material- Tempered 'Cast Steel 
FULLER/NO BLOCK 






< 5$" - — > 

Tool Steel hardened all over 


ft 




■*. 5' > 

TOP TOOL 




k 




[<... /L'. J races ground flat-" 
I >- jj 

Fig. 200. — Details of heading punch. 



CHAPTER IV 

PRESS TOOLS IN CLOCK AND OTHER MANUFACTURE 

Some Sub-press Dies. — The Seth Thomas Clock Company, of 
Thomaston, Conn., makes most of its own dies, and the accom- 
panying drawings show some original ideas that the* concern 
has perfected and introduced from time to time in connection 
with its die-making methods in order to obtain the best possible 
results. Credit should be given to C. H. Bell, foreman of the die 
room and G. B. Buckland, head diemaker. 

A Novel Set or Pillar-press Tools 

Here is a set of tools for cutting out clock plates, or clock 
frames, as they are also called, that will stand up and run day 
after day without requiring the services of a diemaker to keep 
them going is an A-l job, as clock plates are usually made of, say, 
0.050-in. metal, and have anywhere from 25 to 50 or more holes 
pierced, many of the holes being of the same diameter as the 
thickness of the metal. It is, therefore, obvious, that not only 
the punch and die, but the press itself that holds the punch and 
die in position and in correct relation to each other, must be 
properly made in order to give satisfactory results. 

The set of pillar-press tools, shown in Figs. 201 to 203, produce 
the circular clock plate in Fig. 204. That press tools constructed 
as here shown will accomplish all that is desired, may be illus- 
trated by referring to Fig. 205, which shows a brass clock plate 
0.055 thick made in one operation and containing fifty-three 
holes (not all shown) , many of the holes being of the same diam- 
eter as the thickness of the metal; yet 7 tons were cut at one run 
without the breaking of a punch or a minute's stop for repairs. 

Fig. 201 gives a general idea as to the construction of the 
tools which are used for cutting out the circular plate, shown in 
Fig. 204, which is made of 0.055 metal and has twenty-eight 
holes pierced and seven prick-punch marks which are all made in 
one operation. When it happens that the required size of cer- 
139 



140 



PRACTICAL DIE-MAKING 




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PRESS TOOLS USED IN CLOCK MANUFACTURE 141 

tain holes is less than the thickness of the metal to be used, 
the locations for these holes are pricked by a punch made 
similar to the round piercing punches, except that it is pointed 
and made a trifle shorter. This saves the time of drilling out 
the holes later on by the aid of a drill jig. 

The Construction of the Tools 

After the upper and lower members have been machined and 
the four pillar posts placed in position, as shown in Fig. 201, 
the fixture shown in Fig. 206, which fits the hole recessed out for 
the lower die, is set in, and the upper member slipped over until 
the bottom of the hole recessed out for the punch holder tests 
on the fixture, thereby bringing the upper and lower holes exactly 
in line with each other. 

The babbitt is next poured into the open space between the 
bushings and the frame of the press, and is composed of a special 
mixture, which has been found to be less liable to shrinkage than 
any other composition they have experimented with, and is as 
follows: Six parts of lead, two parts of tin, one part of bismuth, 
one part of antimony. 

When thoroughly cool the upper member is worked up and 
down to detect any unncessary play or looseness of fit; also to see 
if the upper and lower holes are in an exact alinement with each 
other. The flanges on the bushings are then secured to the frame 
of the press by four pins, and the four projecting shoulders of 
the frame of the press near the threaded part of the bushings 
are now beveled off by a special revolving cutter which has a pro- 
jecting tit which fits the hole in the bushing. The nut which 
screws onto the bushing is beveled on the inside to correspond 
with the bevel on the frame of the press. "When the nuts are 
tightened up, they not only prevent the bushings from working 
down, but also hold them central with the beveled shoulders on 
the frame of the press regardless of the babbitt. 

It will be seen that the babbitt plays no part in the working 
of the tools, that its chief aim is to help line up the upper and 
lower members with each other and hold them in this position 
until the bushings are pinned in position and the nuts tightened 
up. 

Fig. 202 shows a cross-section view of the working parts of the 
lower member of the pillar press. 



142 PRACTICAL DIE-MAKING 

The Lower Die 

The lower die is held in place by three }>i-in. fillister-head screws 
in the flanged part of the die which fits in the recess of the press 
and is further prevented from turning by a 3^-in. locating pin; 
this pin also locates the die in its exact position whenever it is 
taken out and put back in place. 

By referring to the clock plate, Fig. 204, the shape of the face 
of the die can be readily seen; the die is made from an accurate 
master plate containing the various holes which are in the exact 
position and relation to each other required. 

The Stripper 

The stripper is made a nice sliding fit on the outside of the lower 
die, and strips the metal from which the plates are cut from this 
die by the aid of three springs, as shown. 

A very ingenious method is used to control the upward motion 
of this stripper. Of the various methods tried in the past by this 
• concern the one illustrated has proved to be the best, and is now 
used in connection with all dies of this kind; also when occasion 
requires no regular subpress tools. 

As shown, the threaded part of the three screws that screw into 
the stripper from the bottom are prevented from working loose 
by the three check screws that are screwed into the face of the 
stripper. The threaded thimble is drilled and counterbored to 
receive the head of the screw, as shown, and has a screw-driver 
slot by which it is screwed into the frame of the press. This 
thimble controls the upward motion of the stripper and is pre- 
vented from turning or loosening by a headless screw which forces 
the brass plug into the threaded part of the thimble, as shown in 
Fig. 202. 

The Upper Die Ring 

Fig. 203, shows the working parts of the upper member of the 
pillar press and consists of the upper die ring which is held in place 
by six % 6 in. fillister-head screws. The inside of this die ring 
fits the outside of the lower die and cuts the circular or outside 
form of the clock plate, as shown in Fig. 204. 



PRESS TOOLS USED IN CLOCK MANUFACTURE 143 

The Shedder 

The shedder is made a nice sliding fit in the hole in the die ring, 
and not only sheds the clock plates from the punches, but helps 
to keep the punches in line with the lower die, and also supports 
them and prevents them from springing or breaking. 

The holes in the shedder for the different punches are trans- 
ferred from the lower die after the die is hardened and set in 
place. The shedder is left soft for fear of distortion of the steel 
in hardening; so that the holes for the punches are in an exact 
line with the holes in the lower die and this plays a most im- 
portant part in the successful working of the tools. 

Securely fastened to this shedder by the aid of screws and dowel 
pins is a hardened steel disk, upon which six pins are continually 
pressed by springs, as shown in Fig. 201. The holes in this disk 
for the punches are made large enough so that the punches do not 
come in contact with it. The hardened disk prevents the shedder 
from being roughed up by the six operating pins. 

The Punch Holder 

The punch holder, Fig. 203, for different punches is held in the 
upper member of the press by three M _m - fillister-head screws 
and a M _m - locating pin. The holes into which the various 
punches are driven are laid out from the same master plate that 
was used in laying out the holes in the lower die. 

The Punches 

The piercing punches are lightly driven in from the back and 
are prevented from pulling through by the flanged head, as shown. 
The punches which cut out the larger of the irregular holes which 
are marked G in Fig. 204, have taper shanks which are driven into 
the punch holder, and are still more firmly held in place by the aid 
of screws and dowel pins. 

Stamping the Trade-mark 

When it so happens that the clock plates are to be stamped 
with a trade-mark, or lettered or numbered in any way, the 
device shown in Fig. 207, is used in connection with the tools 



144 PRACTICAL DIE-MAKING 

described. The operation is done at the same time the plate 
is cut and pierced without added expense insofar as the operat ion 
itself is concerned. 

This method, which is original with the Seth Thomas Clock 
Company, is the result of considerable experimenting, and is at 
present used when required on all tools of this type with the best 
of results. 

Referring to Fig. 207, the trade-mark punch, the outside of 
which is made a nice sliding fit in the shedder, is lightly driven 
into the punch holder. The steel pin shown not only prevents 
the punch from turning and dropping through in case it becomes 
loose in any way, but also helps to locate it in its proper position 
when put back in place after it has been taken out. The hole 
for the pin is elongated to allow for the adjustment of the punch. 

The distance from the face of the trade-mark punch upon 
which the design for the trade-mark is cut to the face of the 
shedder is equal to the thickness of the metal to be used. The 
round steel piece A, together with the adjusting screw, forms 
the means for adjusting the trade-mark punch in order to give 
the proper depth to the trade-mark when stamped on the clock 
plate. The adjusting screw bears against the shoulder of the 
button as represented and is prevented from loosening by the 
brass plug B which is forced against the head of the screw by the 
screw C. The screw D prevents the part A from loosening and 
also prevents it from turning when the adjusting screw is raised 
or lowered. 

It should be stated that the four pillar posts have the usual 
spiral grooves to facilitate oiling; also that the arrangement for 
feeding and guiding the metal in connection with these tools is 
not shown, but is similar to those generally used and needs no 
explanation. 

A Novel Set of Subpress Tools 

This set of subpress tools is of more than ordinary interest, 
due -to the fact that they cut and pierce four blanks at one time. 
Fig. 208 shows the lower member of the subpress with a plan of 
the punches and work just above in Fig. 209. Fig. 208 includes 
the usual form of stripper whose upward motion is controlled 
in the manner indicated; it is similar in construction to the 
one already described in connection with Fig. 201. 



PRESS TOOLS USED IN CLOCK MANUFACTURE 145 

The Stripper 

The face of the stripper is represented in Fig. 210 and is made 
in five parts, as shown, to facilitate the working out of the 
irregular-shaped holes which are made a sliding fit for the blank- 
ing punches. 

The small round hole numbered 1 is the hole where the 
punch comes through which pierces the hole in the metal for 
the gage pin. This punch is held in place in the lower member 
of the subpress, and is shown in Fig. 209. 

Hole 2 is the escape hole for the punchings from the gage- 
pin hole, while the hole numbered 3 is the hole for the gage pin. 

The Blanking Punches 

The manner in which the blanking punches are held in posi- 
tion in the lower member is shown in Figs. 208 and 209. Fig. 
209 shows the punches in position with the stripper removed. 
The round flanges on the blanking punches are fitted into the 
recessed holes and are held in place by screws and dowel pins. 
The punches when in use perform the function of both punch 
and die, as the punches also act as piercing dies for the small 
round hole in the blank. The small holes shown in Fig. 208 are 
the escape holes for the scrap punchings that are thus pierced 
out. 

Laying Out the Die 

In laying out the die there were three important points taken 
into consideration : The first was to construct the die so that 
it would be strong enough to do the work. The second was to 
lay the die out so that the greatest number of blanks would be 
cut from the least amount of metal. The third was to lay out 
the die accurately so that there would be no "running in," that 
is to say, no cutting of imperfect or half-blanks when running 
the metal through on account of "a wrong layout." 

The Construction of the Die 

Figs. 211 and 212 show that the die is made in five sections 
which are held in place by screws and dowel pins. The die 
itself is held in the upper member of the press by four fillister- 
head screws and the usual locating pin. 

10 



146 



PRACTICAL DIE-MAKING 



By referring to Fig. 213, which shows a strip of metal after 
it has been run through the press, it can be seen that the metal 




The Blank 
(.ois'siook) \ O 



Fig. 210. 




ISbedSera ShiJJor fur I 

/ Hole." 1 \ 



4 Piercing Punches. 

Fig. 212. 




Fig. 209. 



Fig. 211. 



ljuuiiuns runcDes , Pu£h piDB y////A 



Fig. 208. 




Fig. 213. 





Fig. 214. Fig. 215. Fig. 216. Fig. 217. 
Figs. 208 to 217. — Subpress tools for clock hands. 

is pretty well used up, that there is very little stock left that has 
not been converted into blanks. 

Fig. 211 shows the layout of the die, which is made so that 



PRESS TOOLS USED IN CLOCK MANUFACTURE 147 

the points numbered 1 and 2 point toward each other while the 
points numbered 3 and 4 point just the opposite way. This is 
done to allow the holes in the metal from which the blanks 
have been cut to match up more closely with each other; that is, 
more metal would be wasted if the die was laid out so that the 
circular bodies of the blanks were all cut in a straight line with 
each other. 

Accuracy in Layout 

In laying out the die the first step to be taken after the manner 
in which the blanks are to be cut from the metal has been decided 
upon is to find the distance from D to E, Fig. 213, which is done 
by adding the width of the blank to the bridge of metal. In 
order to make the die strong the irregular holes are spread apart 
in the manner shown in Fig. 211. The distance from the center 
of these holes (which are numbered 1 and 3, 2 and 4) is ac- 
curately spaced off by taking the distance from the center of 
the hole D to the center of the hole E in consideration. In this 
case the distance from the center of 1 to the center of 3 is seven 
times the distance from D to E. It can readily be seen that this 
distance must be exact, for the reason that if it was too long 
there would naturally be- an unnecessary waste of metal, owing 
to the fact that there would be too large a bridge of metal be- 
tween the holes after the metal had been run through. On the 
other hand, if this distance was too short the holes would run 
into each other as the metal was being gradually run through, 
which would mean that the blanks cut would be imperfect or 
half-blanks. 

The distance that 1 and 2 should be located from each other 
is determined principally by the relative strength of the die 
between the holes, as is also the distance between 3 and 4. 

Running the Metal Through 

The metal is run through in the usual way by the aid of guide 
pins, not shown. The short section of metal shown in Figs. 
214 to 217 clearly shows how the metal is run through from the 
start, also how the holes gradually match in with each other 
after the fourth stroke of the press. 

It must be understood, however, that the blanks are pushed 
back into the metal by the upper shedders (shown in Fig. 212) 



148 PRACTICAL DIE-MAKING 

after they are cut, and are taken out after the metal has been run 
through. The holes in the short strips of metal are drawn 
merely to give a clearer idea as to the manner in which the blanks 
are cut from the metal, also to enable the reader to more readily 
grasp the idea as to the manner in which the die is laid out. 

Fig. 214 shows that on the first stroke of the press four blanks 
are cut, as is also the hole for the gage pin. The blanks arc 
pushed back into the metal by the shedders, which also tend to 
straighten or flatten them out in doing so. 

The scrap punching from the gage-pin hole is also pushed back 
into the metal by the shedder shown in Fig. 212, as there is 
no convenient way in which the punching can be gotten rid of by 
allowing it to escape by way of the upper member of the press. 

Fig. 215 shows the metal after the second stroke. The scrap 
punching from the gage-pin hole that was cut on the first stroke 
of the press is now pushed through the metal by a push pin 
shown in Fig. 211, and allowed to escape through the hole 
numbered 2 in the stripper shown in Fig. 210 and drops through 
the hole in the frame of the lower member of the press which is 
shown in Fig. 209. 

By referring again to Fig. 215 it will be seen that the distance 
from the center of one gage-pin hole to the center of the next, as 
shown at C, is the same as the distance between the centers of 
the irregularly shaped holes A and the centers of B, and that 
after every stroke of the press the metal is fed or moved along 
just this distance, until the entire strip of metal has been run 
through. 

After the second stroke of the press the gage-pin holes engage 
with the gage pin and form a position stop for the metal, thus 
preventing the feeding of the metal too far or not far enough 
when passing it through the dies. 

Figs. 216 and 217 show the metal after the third and fourth 
stroke and also show how the holes in the strip gradually match 
up with each other until it appears like the strip shown in Fig. 213, 
after it has been run through. 

Split Dies 

The split dies shown to reduced scale in Figs. 218 and 220 
are used for blanking out clock hands, and are shown merely to 
give an idea as to the manner in which the blanking dies for this 
operation are made. 



PRESS TOOLS USED IN CLOCK MANUFACTURE 149 

Fig. 218 represents a split die for blanking the long clock 
hand in Fig. 219. The two sections are doweled together in the 
manner indicated which prevents them from shifting endwise. 
When in use the die is held in the die bed by the usual key. 

The semicircular notch marked X engages with a round stud 
in the die bed and prevents the die from shifting in the bed when 
in use. This method is used by the Seth Thomas Clock Com- 
pany on all ordinary blanking dies, and while not being new is 
nevertheless one that should be made more use of than it really 




Fig. 218. 



O 



Fig. 219. 





Fig. 221. 

Figs. 218 to 223.- 



Fig. 222. 



Fig. 223. 
-Clock hands and dies. 



is. The key which locks the die in the bed is driven in on the 
other side of the die at K, Fig. 218. 

Fig. 220 shows a split die that borders on the artistic, and is 
used for cutting the outside form of the clock hand in Fig. 221. 
The fancy perforations on the inside of the blank are made in 
a separate operation. 

Fig. 222 is another artistic blanking die for the clock hand in 
Fig. 223. This die is not split for the reason that the blank is 
of such a design that it cannot be halved by a straight line. The 
perforations here are also left for a separate operation. 



150 



PRACTICAL DIE-MAKING 



A Subpress Perforating Die. — It is generally considered bad 
practice to use perforating dies in a long-stroke press as they do 
not usually give satisfaction. The illustration shows a perfor- 
ating die for fruit graters for a press with a stroke of 33^ in. 
The die had to punch four rows of twenty-eight holes each, and 
from one side of the holes to a lip, as shown in the half-tone, 
Fig. 224. The holes in the die were No. 45 drill size, eight holes 
to the inch. 

To overcome the long stroke of the subpress, the die illustrated 
was designed and proved a success. 

Fig. 225 shows the assembled die. The bedplate of the die 
A is a machine-steel plate, onto which the subpress housing B is 
fastened by means of four capscrews C. Into this subpress 




b fe fe '»*»»* fe b t 

Jklfe 1* ifc k .-Wk k ^ ft fa k » 



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Fig. 224. — Perforations in a fruit grater. 



housing a machine-steel sleeve D is fitted, a nice sliding fit. 
This sleeve D is planed at the bottom to receive the punch plate 
E, which is fastened to the sleeve by six flat -head screws. 

The lower die F is fastened to the machine-steel bedplate by 
six flat-head screws in proper alinement to the punches. 

The stripper G is fitted to the punches a nice sliding fit, and 
four %-in. pins 1,1 (two of them only shown) provide a guide for 
the stripper. The four pins I are a driving fit in the bedplate 
A and in the subpress housing B, and are a sliding fit in the 
stripper G. Two slots are worked through the subpress opposite 
each other at KK and two }4,-m. tapped holes put in the slide D. 



PRESS TOOLS USED IN CLOCK MANUFACTURE 151 

The two screws L,L are screwed into the sleeve D to prevent it 
from turning and from being pulled out of the subpress. 

The plunger M is made of machinery steel, a loose fit in the 
sleeve D, and provided with a shoulder N. The sleeve D is 




Fig. 225. Fig. 226. 

Figs. 225 and 226.- — Subpress perforating die. 



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Fig. 227. 



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Fig. 228. 
Figs. 227 and 228.— Top of die and stripper. 

threaded at the top and the ring is screwed onto the sleeve D 
Fig. 225 shows the punches almost at the lowest position of the 
down-stroke, and the punches (of which one only is shown) ready 
to penetrate the metal. Fig. 226 shows the sleeve with punches 
attached to it, and the plunger M in its highest position. 

The advantage in a die like this is first that only about J^ in. 



152 PRACTICAL DIE-MAKING 

or one-seventh of the press stroke is needed for piercing the 
hole and stripping off the material, and six-sevenths of the time 
the punches are at rest. 

Fig. 227 shows the top view of the die F, and Fig. 228 the 
bottom view of the stripper G upside down. It will be seen that 
the holes in the die F are round holes, with one side worked 
deeper to make it appear oval on the top. 

The stripper is exactly the counterpart of it; the little pro- 
jections on the stripper fit in the depression of the die and are 
the forming parts for forming the grater lips on one side of the 
pierced hole. 

The die is set like any other subpress die. The punches are 
set so deep into the die that the stripper and punch plate come 
close together. This is necessary, because the stripper has to do 
the forming of the grater lips after the punches have pierced 
the material. The stroke of the press is then adjusted, so that 
when the crank is at its highest point the shoulder of the plunger 
M has pulled the sleeve D with the punches up. In doing this 
the stripper goes up with the sleeve about 34 in. strikes the 
subpress housing at P, and strips the material from the punches. 
The punches stop in this position awaiting the down-stroke of 
the plunger. In this manner the long-stroke press was used 
satisfactorily. 

Subpunching Clock Wheels. — Fig. 229 shows a subpress die 
and set of tools for a five-armed brass wheel. As in other work 
of this kind, the wheels are returned to the strip of brass and 
carried along with it, to be removed later. 

The punch is made up of five sections A for the five openings 
between the wheel arms. These sections when assembled are 
secured in the holder B which also carries the pier ing punch 
C for the central hole in the wheel. The outside the M, by 
which the wheel is blanked, is located as shown, with the shedder 
E occupying the annular opening between the die D and the 
exterior of the punch sections A . 

The lower die is composed of a central spider F, milled out so 
as to leave five ribs of the right thickness for the arms of the wheel. 
Over this central member the shell G is tightly fitted. This has 
shallow, vertical grooves in the interior to receive the edges of 
the ribs and prevent them from springing sideways when the 
die is in operation. 

The die case H and the bottom shedder / are arranged as 



PRESS TOOLS USED IN CLOCK MANUFACTURE 153 




154 PRACTICAL DIE-MAKING 

indicated in the sectional view. Other details of tools and sub- 
presses are also clearly shown, making further explanation 
unnecessary. 

Building a Sectional Subpress Die. — This assumes that the 
subpress is already made and that the babbitt bearing has been 
cast with the piston in place ; also that the piston has been ground 
to a finish and the base of the press has been roughed out. 
When the piston is drawn from the bearing, it comes out with 
difficulty and it will be noticed that the babbitt has a dark 
glazed surface. This dark glaze does not signify that the piston 
bears all over, as the babbitt usually contracts more at the bottom 
than at the top. The glaze should be removed by scraping, 
taking off as little as possible. If the piston is worked up and 
down in the bearing a few times, it will show where it bears and 
it should be scraped until a good bearing is secured. If, after 
scraping, the piston works too freely, close in the babbitt by 
means of the nut N at the top in Fig. 230. Owing to friction, 
it is difficult to turn the nut when forcing the babbitt down, but 
as there is always some play in an ordinary thread, by tapping 
the nut with a piece of lead the babbitt can be driven down and 
the taper will close it in on the piston. 

The piston should bear well all over and fit tight enough so 
that A and B, Fig. 230, can be machined, using the centers of 
the piston to swing the job. Although the piston has been 
ground from its centers, it should be tested with the indicator to 
see if it still runs true. A good indicator is indispensable on this 
class of work and should be used freely, as a few movements 
with this tool will show the slightest error and save time when the 
die is assembled. 

If the piston fails to run true the center or centers in error 
should be rebored. The piston should then be inserted in the 
press and seat surfaces A and B, Fig. 230, machined to a finish. 
For the finishing cut a keen tool and slow feed should be used, 
giving the tool time to cut a smooth, true surface. Before re- 
moving from the lathe the cut should be tested for truth. 

The base of the subpress, Fig. 231, should be swung on the 
faceplate and all the seats worked at the one setting, the same 
care being exercised as in the preceding operation. When using 
the faceplate on the lathe, great care should be observed to have 
it run true if true work is desired. 

For boring the seat in the piston for the die and shedder, the 



PRESS TOOLS USED IN CLOCK MANUFACTURE 155 

steadyrest and split bushing E, Fig. 240, are used. The bushing 
gives a good bearing and cannot be dispensed with, as the oil 
grooves in the piston, if held without the bushing, cause it to 
jump when they strike the jaws of the rest. 

Insuring Concentricity 

The die holder D, Fig. 230, may be finished to size, slotting 
the clearance for the blades of the shedder at E, and turning the 
seats for the shedder and die concentric with the part of the holder 
which rests in the seat of the piston. The surest way to have 
the seat for the die concentric with all other seats is to bore it 
after it has been screwed and doweled to the piston, using the 
split bushing E, Fig. 240, and a steadyrest. The holder for the 
sections of the shedder part C, Fig. 230, may also be finished, 
but the hole for the punch and shedder parts C and D, Fig. 231, 
should be left a little larger in diameter than the seats, so that a 
finish cut may be taken later. 

The blanks for the sections of the punch, die and two shedders 
are roughed out, leaving about 0.015 in. on the face for grinding 
and about % in. on the outside diameter. Lines are laid out, 
crossing each other at right angles and 3^2 m - from the center, as 
shown in Fig. 236. The intersecting points of these lines are to 
be the centers of the finished die, punch, and so on. These 
points should be prick-punched, and by laying out each section 
from its own center, we can cut into the sections and machine to 
the lines. Before quartering the blanks, the stock on the punch 
and die shedder are milled away as required ; then putting in dowel 
and screw holes, the blanks are ready to quarter. Each section 
should be machined, leaving an allowance for grinding. Owing 
to the method to be pursued, the hole in the center cannot be 
bored, so the pieces are hardened. 

Grinding the Sections 

The work is now ready for the block shown in Fig. 234, 235 
and 237. This is made large enough to suit the work, and with a 
base wide enough to insure it standing squarely upon the magnetic 
chuck of the grinder. Particular pains should be taken to get 
it as nearly square as possible, as the squareness of the sections 
depends upon the squareness of the block, and unless the sections 
are square, the die is worthless. 



156 



PRACTICAL DIE-MAKING 

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PRESS TOOLS USED IN CLOCK MANUFACTURE 157 

Strapping the sections upon the corner of the block, as shown 
in Fig. 237, the surfaces E can be ground, measuring from A to 
B and from C to D. Had the central hole been bored while the 
sections were soft, it would be more difficult to measure with the 
required degree of accuracy than it is direct from the corner. 
This side finished, the block is turned over and the operation 
repeated on the surfaces F. 

In grinding the sections shown in Fig. 234, we must see that 
they are ground so that the dowel holes line up. The first step 
for grinding the center hole is shown in Fig. 235. By bringing 
each section to bear upon the knife-edge pieces A, all the sections 
can be ground exactly alike. They should all be roughed first and 
then finished without disturbing the wheel. 

Grinding the Hole 

When the sections are screwed upon a plate for holding them 
while the hole and outside are ground, pieces of stock of the 
proper thickness are placed between the sections. For the die 
shedder pieces 0.0205 in. thick are used and for the other three, 
pieces 0.0193 in. thick are used. When the die shedder is ground 
and put into the holder it is finished, as the holder fits freely in 
C, Fig. 230. The die shedder has no purpose other than shedding 
the die of the blank, so, therefore, the holder can be finished in- 
dependently, taking the usual care to have the hole in the center 
of the sections come in the center of the holder. 

Screwing the sections in position on the plate for grinding re- 
quires the greatest care, as the position of the sections on the plate 
when they are ground is the same as the position they occupy 
when they are in their holders. 

The assembly for grinding on the die and punch shedder is 
shown in Fig. 239. The size of the plugs A should be such as 
will allow the sections when screwed together by means of the 
spider, to hold the plugs in place and have the slots B the proper 
width. When the sections are screwed on the plate so that each 
plug touches both sections at the end of the slot, and the pieces 
of stock 0.0195 in. thick are a sliding fit, then put a round plug 
in the square hole in the center, swing all on the faceplate, locat- 
ing so that the plug runs dead true and then grind the hole and 
outside to finish sizes. 

In Fig. 238 the plugs A are used to locate the sections the same 



158 PRACTICAL DIE-MAKING 

as the plugs in Fig. 239. In grinding the outside no allowance 
should be left for drive, as this will cause the sections to close 
in. The sections should now be screwed and doweled in their 
respective holders. 

Finishing the Holders 

In Fig. 240 is shown the method for finishing the holders for 
the punch and punch shedder. The punch shedder is important 
as it guides the blades of the punch. The punch is pushed 
through the shedder from the bottom. The part E is a ring of 
steel which has been ground so as to have the same width at all 
points, and is made just wide enough to keep the parts of the 
punch, other than that part touching the ring, from bearing on 
the shedder. The portion of the punch protruding from the 
shedder is entered into the die, the part C placed between the 
center and the bottom of the punch and the center brought to bear 
just hard enough to bring the punch and shedder squarely against 
the die, which has been screwed and doweled to its final position 
in the press. With the test indicator, the piston nearest the die 
holder should be tested and also the bottom of the punch and 
shedder. If they all run dead true, conditions are then ready 
to finish the punch and shedder to fit their seats in the base of 
the press. 

Assembling 

The top and bottom of the press have already been screwed and 
doweled together. The punch and shedder are now inserted in 
the die in the same manner as they are in Fig. 240, using the same 
ring in the same place. In this position the punch and shedder 
should be pressed into their seats and screwed and doweled. It 
will be remembered that the die was left 0.001 in. small. This 
was done to have it a fit for the punch, so that we could perform 
the preceding operations. These sections should now be taken 
out and ground or lapped 0.0005 in. on all the parts which are to 
cut. We will then have 0.0005 in. spare between the punch and 
die all around, insuring a clean break and no burr. 

Tools Used in Making Eyeglass Bridges. — As generally made, 
the fingerpiece eyeglass bridge consists of a piece of round wire, 
cut to a define length, and then worked into shape by a number 
of machine operations. 

The first six of these operations are shown at Fig. 241, where A 



PRESS TOOLS USED IN CLOCK MANUFACTURE 159 



represents the blank cut to length in a press tool, B after the first 
upsetting operation, C after the second upsetting operation, both 
done in the special tool shown in Fig. 242, D after flattening the 
pad in an ordinary striking die having a flat-bottomed punch and 
set in a subpress, E after hollow milling the tit by means of the 
special fixture, and F after having the tap drill-hole pierced with 
the punch and die shown in Fig. 243. 

The special press tool shown in Fig. 242 consists of a body cast- 
ing A, with a pair of dies B,B' arranged in a horizontal slot; one 
B held stationary in the slot, and the other B' fastened in the slide 
C. These dies are held together by the spring D and are opened, 



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B 

Fig. 241. 





C D E 

-Making eyeglass bridges. 



to insert the wire between them, by the lever E. This lever is 
pivoted in the slide, and has an eccentric portion working against 
a pin in the base. 

Sliding vertically in the base are two slides; one F adjusted by 
the screw G, and held against it by the spring shown, which carries 
the upsetting punch, and another H which acts as a cam to close 
and lock the dies B,B' together — also the post I, the purpose of 
which is to prevent the ram block J from turning. The slide 
H is adjustable laterally by the two taper wedges K which are 
adjusted from the top by two screws L. The holder M is for the 
purpose of locating the first pad made for the second operation; 
these pads are of oval cross-section and it is necessary to have 
their major axes in line. This holder slides longitudinally in the 
block N and is prevented from turning by a key in the block 
working in a key slot in M. 

All the slides are milled into the face of the base casting and 



160 



PRACTICAL DIE-MAKIXG 



are held in place by the cover-plate 0, screwed in place as shown. 
It will be noticed that the sliding cam His adjustable in an oblong 
hole in the ram plate. 

Operation of the Tool 

The operation of the tool is as follows: The dies are opened 
by means of the lever E, a blank wire is inserted between the dies 




Fig. 242.— Upsetting dies. 



and pushed up against the upsetting punch in F, the lever is then 
released and the spring holds the blank from dropping. Wheo 
the press is tripped, the slide // forces the dies B,B' together on to 
the wire, gripping it firmly, and locks them together. As the 
press nears the bottom of its stroke, the ram plate comes into 



PRESS TOOLS USED IN CLOCK MANUFACTURE 161 

contact with the punch holder F, forcing the punch onto the dies 
and the stock into the recess shown. All the movements are 
unlocked when the press is at its highest point and the blank is 
removed by opening the dies. The end upset is inserted in the 
holder M and pushed against the upsetting punch as in the first 
operation. 

These pads are upset at the rate of 300 dozen bridges per day 
of 10 hours. A hard wire is used and it is necessary to anneal 
both ends before upsetting; this is done by dipping the ends 
into melted borax at 1200°F. Annealing by means of melted 
borax is believed to be original with the writer and as it is prov- 
ing an excellent method of annealing the ends of temples, bridges, 
and other parts made of gold-filled stock, the process will be 
described. 

Annealing the Stock 

Crystal borax is melted in a pot until the pot is nearly full. 
The first melting of the borax is a deceitful process as it will rise 
and bubble over the top of the pot if much is put in at a time, and 
will not melt until it reaches a red heat. The work, tied in 
bunches, is dipped into the red-hot borax to any desired depth 
and heats almost instantly; the heated ends are then dipped into 
boiling water, removed, and dried in sawdust. Borax is better 
than any other medium for annealing such work as the surface 
of the work where heated is thoroughly protected from oxidizing 
and any borax sticking to the work after heating will be removed 
in the boiling water. There is no danger of overheating the 
work by this method, as the borax may be kept at a constant 
temperature. 

After the bridges have the ends upset they have the ends 
struck to form the clip with a fiat top as described before. 

The punch and die used to pierce the tap drill hole is shown in 
Fig. 243. The complete unit consists of a punch A, made of 
drill rod, held in the punch-holder B, this' being held in the shank 
C by the screws shown. Sliding on C is a stripper D, which is 
pressed downward by the spring E acting through the sliding 
piece F. The stripper is prevented from falling away from the 
shank by the screw G, working in an elongated slot. The spring 
is made of flat wire to obtain the necessary pressure in the 
limited space provided The construction of the die is as shown. 



162 



PRACTICAL DIE -MA KING 



Dies Which do not Waste Stock. — This shows a set of follow- 
on tools which have given satisfaction in actual service. They 
were set up in a No. 20 Bliss press running at 80 r.p.in. with a 
single roll feed, turning out 160 finished brackets per minute. 
The tools are in constant use every day, and to avoid delay, a 
second set of tools has been made so that one set can be running 





Die Bed 



Fig. 243. — Piercing punch and die. 

when the other set is being repaired. It is not unusual for these 
tools to run 120 hours and then they only require sharpening, 
about an hour's job for the tool setter. 

The finished articles are shown in Fig. 244. They are used 
for supporting spring roller blinds, are made from strip steel ] ,^_> 
in. thick and are pierced, embossed, bent at a right-angle, and 




Fig. 244. — Curtain bracket. 



blanked in one operation without waste of stock, except the 
piercings. 

A view of the strip steel after the seventh stroke of the press 
is shown in Fig. 245. After the seventh stroke two finished 
brackets, left and right, as shown at Fig. 244, are produced at 



PRESS TOOLS USED IN CLOCK MANUFACTURE 163 

each stroke of the press. One bracket falls into a box under the 
press and the other shoots away from the tools as it is cut off on 
the end by the punch G, Fig. 247, and falls into a barrel at the 

















I 




1 












J 1 ' 1 


1 ' ll ' 




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M 


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H 
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Fig. 246. Fig. 248. 

Figs. 245 to 24S. — Stock saving dies. 

back of the press. The strip steel comes in reels weighing about 
70 lb. each and is fed to the tools by a single roll feed attached 
to the front of the press, feeding front to back. 



164 PRACTICAL DIE-MAKING 

When starting the press the stock is fed in by hand to the 
stop A, Fig. 246, then the roll feed is put in action, the stop A 
will now be idle as the spring keeps it out while the press is run- 
ning. The part B acts as a positive stop when the bending and 
cutting punch R has done its work, the stock will now be allowed 
to pass along the width of another blank, when the blanking 
punch M will perform the operation leaving the strip steel as 
shown at C, Fig. 245. 

The next operation is the embossing shown at D, which is 
followed by piercing the slot E. Bending at right angles follows 
as shown at F. The last operation is performed by the cutting 
punch G, Fig. 247, when the finished bracket shoots off into a barrel 
at the back of the press. The piercing and blanking die S and 
T is made in two pieces to avoid trouble in the hardening. They 
are then screwed to the mild-steel bolster H, Fig. 246. The em- 
bossing and piercing dies I and J are made of tool steel and are 
a driving fit in the mild-steel plate U, Fig. 246. All the piercing 
punches are made of drill rod upset on the end and a good fit 
in the }^-m. drill-rod sleeves, which are a driving fit in the pad 
L, Fig. 247, which is fastened to the punch holder by six %-m. 
fiat-head screws and four %-in. dowel pins. The blanking punch 
M, Fig. 247, should be left long enough to push the blank through 
the die. The bending punch 0, Fig. 247, has two pressure 
pins, one only being shown at P, Fig. 248. These keep the work 
in position while it is being bent at K, Fig. 246. 

These tools have been in use over six months, and they are as 
good today as when first made, new punches and parts being 
replaced as they wear or get broken. A youth can run two 
presses, comfortably making 320 brackets per minute. 

An Interesting Punch and Die. — We recently made a die for 
piercing seven ^32-in- holes through aluminum 0.040 in. thick. 
A description of the tool used might interest others, as it is 
ordinarily difficult to punch a hole of a diameter less than the 
thickness of the metal. 

In this case it was not possible to make an ordinary subpress 
die such as is used by watchmakers, for, as will be seen by Fig. 
249, the holes are in the top of a shell nearly an inch deep, and 
the punch-holder, therefore, has to have sufficient stroke to allow 
the piece to be put on and taken off. 

As will be seen from Fig. 250 the punches are but little over 
Y± in. long and are a snug sliding fit in A. The rods B are a 



PRESS TOOLS USED IN CLOCK MANUFACTURE 165 



snug sliding fit in the punch plate C, the back plate D and the 
punch-holder and stem. This means that the punches are rigidly 
supported when they enter the metal and during the stroke. 
The rods B are rigidly connected at the top by the piece E 
which has in the center a screw F, which acts as a striker for the 
knock-out in the press. 




Fig. 251. 
Figs. 249 to 251. — Piercing die and its work. 

The locknuts on the rods come solidly against the stem of 
the punch-holder, so that there is no danger of the punch or 
stripper being broken by bad adjustment of the press. In 
operation the punches lift the piece off of the die, where it is a 
loose fit, and it is stripped at the top of the stroke. The press 
being inclined, it drops off at the back, leaving the operator 
with both hands free for feeding. 

The punch plate C is held by the beveled edge of G against 



166 PRACTICAL DIE-MAKING 

the block D. The piece G is held by two screws and two pins 
in the same manner as the die holder. The die H, stripper, 
punch plate, and the back block were all turned from a rod of 
tool steel and hardened. The pieces J and G are cold-rolled steel, 
left soft and fitted after the working parts had been hardened. 
The punches themselves are made from piano wire, which we 
used without heating, finding that we could upset them suf- 
ficiently without drawing the temper. 

The die is mounted in a shoe and punch-holder having two 
1-in. subpress pins mounted a little to the back. The bosses 
around the pins come together at the bottom of the stroke so as 
to avoid the possibility of setting the punch too low. The pins 
are fast in the die and a sliding fit in the punch-holder. 

This die gave good results the first time it was used and has 
continued to do so. It was made by one man in less than two 
days. 

Progressive Drawing, Piercing and Blanking Dies. — The 
samples shown in Fig. 251 represent a most successful and in- 
genious example of die work for the progressive drawing, pierc- 
ing and blanking of brass work. This shows pieces of the stock 
of four different pieces all made by the same process, three of 
which are made in eight stages and the smaller piece, a lock 
escutcheon, in seven stages. The larger piece shown in Fig. 
251 is of sheet steel 0.020 in. thick and the draw is % in. deep. 
It is remarkable to make as deep a draw as this at the rate of 150 
per minute progressively without annealing, for not only must 
the tools be made correctly but the stock must be suitable. 
The other three pieces shown are brass of about the same gage 
as the steel mentioned. 

All of the dies are used with a roll feed. Fig. 252 shows the 
dies for the second largest piece shown in Fig. 251. Fig. 252 
is not to scale or in proportion, but is merely to show the general 
principle on which the dies are made. They are of the subpress 
type and must be accurately made. The lower half contains 
the perforating die marked A-\ and the seven punches marked 
B-l to H-l. The top half contains the perforating punch marked 
A and the seven dies marked A to H. The end view of the upper 
half partly in section in the center of drawing die B shows the 
automatic knockout marked M, one of which is in every die from 
B to H. These are actuated by the round rocker bar marked 
7, the shape of which is plainly shown in the sectional end view. 



PRESS TOOLS USED IN CLOCK MANUFACTURE 167 

This rocker bar is actuated by a lever not shown which is fast- 
ened at 8 on the bar 7. This lever is connected to the press bed 
by a rod fastened at the proper point, to give it its movement 
on the up-stroke of the press. At the first stroke of the press the 
strip of metal is perforated by the die marked A-l. The second 
stroke repeats this operation, leaving a round blank, still fast- 
ened to the stock by the two side members which are plainly 
shown in Fig. 251. 

The object of these perforations is to put the stock into drawing 
shape to avoid the buckling which would otherwise make this 
job impossible. The third stroke makes the first draw by the 
punch B-l into the die B. The drawn piece is stripped from 
the punch B-l by the spring stripper marked 6 and positively 




Fig. 251. — Work from progressive dies. 

ejected from the die B by the ejector M. In the fourth stroke 
the first draw goes over the punch C-l while B-l is making another 
draw, C-l and C are identical in size and shape with B-l and 
B and herein lies the secret of the success of the whole job. 
They start off the register for the succeeding operations right 
and keep it so. D-l is the second drawing punch. E-l and 
F-l are the succeeding ones. G-l is the perforating punch which 
acts with the die G. The plugs are ejected by the ejector M ; 
H-l is the final blanking punch which completes the operation. 
These dies are used in an inclined press and are run on brass 
about 200 r.p.m. The spring stripper plate 6 rests normally 
above all punches as shown by the dotted lines in the side view. 
In the top view of the lower half the stripper plate is raised by 
the springs held in the depressions marked X. The superin- 



168 



PRACTICAL DIE-MAKING 





PRESS TOOLS USED IN CLOCK MANUFACTURE 169 

tendent of the works said that it could be accomplished only 
by using a special lubricant. This lubricant is made of fish oil 
and white lead. 

Double-operation Die. — This die, shown in Fig. 253, completes 
two operations at one stroke of the press, it cuts out the bottom 
of a drawn pan, 8 in. diameter in the bottom, 10 in. at the top, 




Inner Shell 
Fig. 253. — A double-operation die. 



\}/i in. deep, and at the same time flanges up the bottom of the 
pan % in. high, and forms the bottom of a small water pail, 
without any waste of material, or any extra labor on the part of 
the operator. 

The die works as follows : When the punch is at the highest 
point of the press stroke, the stripping, or gage ring (actuated by 
springs) for the taper shell moves up so that the pan will rest on 
top of the cutting edge of the lower die, properly locating the 
pan. 



170 PRACTICAL DIE-MAKING 

The punch has also a cutting edge inserted on the inside of 
the main punch, and on its downward stroke this cuts out a 
certain-sized blank and carries it down on the inside of the die 
forming the blank into the pail bottom. When this blank is 
cut from the bottom of the main pan and while the cutting punch 
is descending on the inside of the die, the outer punch is form- 
ing the flange on the outside die, and the moment the press 
starts back on its upward stroke, the spring ring on the outside 
follows the punch up to a certain point, stripping the outside 
taper shell from the die. It is left loose so that it can be easily 
removed. The inside drawing ring which is actuated bj r a 
rubber or spring, lifts up the inside shell, or bottom, level with the 
top of the cutting edge. It can then be readily removed from 
the die when removing the outside shell. This rubber or spring 
need not be very strong as there is no drawing, merely forming 
here. 

The inside cutting edge is independent of the main punch, it 
consists of a ring, hardened and ground, setting inside of the 
main punch. A knockout pad in the center is for ejecting the 
bottom from this center punch, making the die simple and at 
the same time economical. There is about %6 m - left for wear 
on the top of the cutting edge- of the lower die, about the same 
amount on the cutting ring of the inside upper punch, and as 
the inside punch is ground off to resharpen, the back of the 
cast-iron pad, or knockout pad, can be faced off to suit whatever 
is removed by grinding on the face of the cutting punch, keep- 
ing the punch and pad in the same proportions. 

Upsetting the Ends of Boiler Tubes. — This shows dies which 
have solved the problem of upsetting boiler tubes without leav- 
ing any marks or grooves. At C, Fig. 254, is shown the header 
with swell or taper neck for the first operation. This expands 
the tube as shown at the upper end of F. The object of the 
expansion is to prevent grooves on the collars, as shown at H. 
The header D was used in upsetting boiler tubes in the old way, 
but it leaves grooves on the collars. This header can, however, 
be used for the second operation and leave a perfectly smooth 
finish, as shown at G. The die B with headers is used for both 
operations. F shows the collar after the first operation done in 
the new way; the end of the collar is the same thickness the 
tube was before the first operation; the heavier part of the collar 
being at the back. G is the finished collar after the second 



PRESS TOOLS USED IN CLOCK MANUFACTURE 171 

operation in the new way. E is the tube before the first opera- 
tion. H is the collar showing the groove when made in the old 
way. A and B are the dies. 



C D 

\ A i 



■I : 


! g ! 




i : 


! H ! 



Fig. 254. — Upsetting ends of boiler tubes. 

The advantage of the new taper header is not only the better 
and smoother finish, but also in the length of collar. With the 
old header (now used for the second operation) collars could 




Fig. 255. — Die for heading stay bolts. 

only be made up to 3 in. long, while with the new or both headers 
collars of 5 in. or longer can be made. 

On a bulldozer or bolt machine, where the two headers can 
be adjusted for use at the same time, collars can be finished 
with one welding heat for both operations, if not over 3 in. long. 



172 PRACTICAL DIE-MAKING 

Die for Heading Stay-bolts. — This device, shown in Fig. 255, 
is used with an air hammer. The sleeve A on the end of the 
die goes flush against the boiler plate and keeps the tool in 
position. The sleeve is split in halves as shown and held by the 
spring B. As the head of the stay flattens out, the sleeve is 
still kept against the plate by the spring C. 



CHAPTER V 

DATA AND SUGGESTIONS ON THE MAKING OF DIES 

While the preceding pages have been filled with suggestions 
for various kinds of dies, this section deals more particularly 
with methods of construction, data as blanks, stripping pressures, 
etc., etc. 




A sectional die for a sheet- 



An Interesting Sectional Die. — An interesting and successful 
sectional die for a sheet-steel rack is shown in Fig. 256. Of 
three unsuccessful attempts, two were to make a solid die for 

173 



174 



PRACTICAL DIE-MAKING 



punching the entire number of holes. In each case some of the 
bridges between the holes cracked in hardening. The third un- 
successful attempt was to make a solid die that would punch 
every other hole in the piece and then index the piece for the 
remaining holes. This die was produced without cracking or 
breaking in hardening, but the work was not satisfactory, be- 
cause of distortion of the thin bridges by the second punching 
operation. A knowledge of these three failures caused the adop- 
tion of an entirely different method, with satisfactory results. 
In Fig. 256, the letter A indicates a finished piece made with 
the die. It is made from stock % in. wide and }{q in. thick, 



I ;-"'I5- 





'V 1*5- 



Fig. 257. — A section of a built-up die. 



and serves as a rack meshing with a pinion. The conditions of 
the mechanism of which it forms a part are such that great 
accuracy is required. The finished piece must be exactly 7.590 
in. long and contain twenty-two holes each 0.325 in. long by 
0.215 in. wide, and the space between the holes must be exactly 
0.115 in. wide. 

This die was built up of individual pieces, so designed that they 
should be exact duplicates, and capable of being produced by 
machine work with very little handwork. A detail of one of 
these pieces is shown by Fig. 257. 

From a bar of ^2 X 1^-in. annealed tool steel twenty-two 
pieces were milled 0.330 X 1 X 1% in. and two longer pieces 
to form the ends. In the twenty-two pieces a slot was milled 
0.215 X 0.375 in. Two holes were then drilled through one of 
these pieces, and this piece was used as a drilling jig to drill the 



MAKING OF DIES 



175 



others. The piece to be drilled was located in the drilling jig 
by means of a square key fitted to the slot which had been 
milled. Then the various clearances were milled, as shown by 
the drawing, Fig. 257. After this, the pieces were milled to 5- 
degree angles to fit in the bolster, and a clearance was milled 
on each of the two upper corners for the set edges. 

A Reliable and Economical Forming Die. — Figs. 258 to 263 
show a method of making a forming die which can easily be 



Fig. 

'258. 




X Dowel Pins 

y % 'Screws 



Fig. 259. 



Cast Iron 
Bolster 



'ifcl D 






m 




Fig. 260. 



Fig. 262. 

Figs. 258 to 263. 



Fig. 263. 
-Details of a forming die. 



repaired, will stand as great a strain as a solid one and also avoid 
the chances of cracking in the hardening. In this case the 
die is hardened and tempered in two separate parts. The work 
for this die is a brass rivet as shown in Fig. 258. 

The first step is to face bolster A, Fig. 259, top and bottom, 
bore and thread hole for bumping and regulation pin K. This 
pin to be of best cast steel and the lock nut, drilled through 
center is to be hardened and tempered. Cut slot D 3-2 in. in 
width for hand lever M as shown in Fig. 260. Tool extractor S, 



176 PRACTICAL DIE-MAKING 

Figs. 262 and 263, is most satisfactory and can be easily fixed 
underneath any press and gives greater power in extracting 
product. 

The base of die is now completed with the exception of screw 
holes for securing die-holder E. Turn die-holder E same diam- 
eter as top of A as shown in Fig. 260. Bore holder E for die F 
leaving }{q in. taper at back. Die F must be turned a nice fit in 
E and to stand about %6 m - above it as in Fig. 260. Bore die F 
same size as shank on work required as Fig. 258 leaving about 
0.004 in. taper at mouth, allowing the product to be extracted 
more easily. See that this bore is nicely polished. Turn cast- 
steel plate G to fit over die F leaving right thickness for the form- 
ing of the square flange as in Fig. 258. Plate G and holder E 
must be secured to bolster A by means of screws and three dowel 
pins. Cut square for flange central with bore in die F. 

This plate G will have the greatest strain and require special 
attention in hardening and tempering. Temper to almost blue, 
die F to be left harder only tempering to light straw. Plate G 
can be changed for different shaped flanges as required. It can 
also be repaired easily, as this is the part where the wear and 
tear in a solid would take place, necessitating a new die through- 
out. Plunger H must be of cast steel hardened. The jack I 
must nicely fit bore in die F. This jack has a centering tit so as 
to center the product ready for drilling which was required in 
this case. Figs. 262 and 263 is the foot extractor fitted with 
hardened steel peg J which works through pin K and forces 
the product out of die. This peg can be regulated if required 
by screwing K into extractor L and fastening with lock nut at N. 
Fig. 261 is the top die or punch which cannot be left too strong. 

A Combined Blanking and Forming Die. — Fig. 264 shows a 
combination blank and forming die for brass caps for carriage- 
bolt heads, such as are used in laundry machines. 

A is the forming punch; B is the blanking punch; C is a split 
sleeve which catches in the groove cut around the forming punch ; 
D is a sleeve that locks and releases the blanking punch. 

The coiled spring E pushes the blanking punch back and locks 
it as you see it on the sketch. F is the punch-holder; G a pin 
through F and A; H, the die pressed into an iron block; 7, the 
blanking part; and J, the forming part of the die. The shoulder 
on B, near the cutting edge, is to hold B, while A goes down and 
forms up the cap. 



MAKING OF DIES 



111 



A Sectional Die that is Easily Made. — A sectional elevation 
of a blanking and drawing die is shown in Fig. 265. This can 
be used on any standard double-action press to make, seamless 
oblong covers with a flange up to Y± in. in width without trim- 
ming, which would be necessary with most dies. The construc- 
tion of this die is such that it can be made in any machine shop 
with the use of their regular machines without going to a regular 
diemaker. 




Fig. 264. — Combined blanking and forming die 



Referring to the illustration, A is of hardened tool steel and 
secured to the wrought-iron bolster plate B by screws C and 
dowels D. The friction ring E is of hardened tool steel and is 
held in place by the pins F, which are driven into the cast-iron 
pad G. The cutting ring H is of hardened tool steel and is 
welded to the wrought-iron plate / which is secured to the bolster 
plate B by screws J. 

The gage pins K are driven into the cutting-ring plate I. The 
punch ring L is of hardened tool steel and secured to the steel 



178 



PRACTICAL DIE-MAKING 




MAKING OF DIES 



179 



punch body M by dowels N. The knockout pad and stem is 
made from one piece of steel and is held in place by the nuts Q,Q. 
The washer R is of cast iron so that it can be taken out and ground 
as the punch ring L gets worn. 

Making a Difficult Die Rapidly. — This die, while quite common, 
is not an easy one to make in the usual manner. It cuts off, rounds 



( o Piece to be made o) ( oj^/ 

\ Fig. 266. 

/ r®l \\ M,/i off Outside fo\ 

i \/Z=\\ ' J Doffed Lines to \ 

\ u@fH J form-Main Punch ) - 




8feD38 




Knockout for Small Punches 






Bore for Punch \ 
Pouna 'Punches 

Fig. 269. 



Fig. 267. 



A 



A 

o 



fOage 



Stripper^ 



Fig. 268. 



Figs. 266 to 269.— Method of making difficult die. 





i 


|a 


B M 


! ! c- 


^ r>- 


C J ! 



the ends and punches the two small holes. Fig. 266 represents 
the piece to be made and one end of the strip. By this method 
you get perfectly rounded ends with the holes accurately centered. 
In Fig. 267 is shown the punch and in Fig. 268 the die, in three 
views. In this method the punch is made first. Fig. 269 shows 
the method of making a punch, most of the work being done on 
the lathe. First turn up the blank as indicated, then finish the 



180 PRACTICAL DIE-MAKING 

shank and lay out the centers of the small punches, as shown in 
A and B. Have an adapter for the lathe faceplate to fit the 
punch shank. Locate one center and bore out complete the 
three sizes, as shown — that is, the inside diameter of cut-off 
punch, the hole for the small punch and also the knockout hole 
for the small punch. Reset to the other center, and repeat. 
Next mill or shape, as shown by the dotted lines C. The punch 
is then practically finished. 

The die is easily made by using two tool-steel pieces inserted 
in a mild-steel die block, as shown in Fig. 268. By making the 
two pieces A exactly the same size, you can clamp them both 
edgewise and almost finish to size in the shaper. This type of 
die is rather difficult to make when made in one piece, as is the 
usual practice. 

Cast-iron Blanking Dies. — It is often necessary, especially 
in a job shop, to make a small number of blanks, but not enough 
to warrant the manufacture of a regular tool-steel punch and 
die. 

If the blanks are not over 0.035 in. thick, the die and punch 
can both be made of ordinary cast iron. Such a set, if properly 
fitted, will produce several hundred blanks equally as well as the 
more expensive type generally used. There seems to be no 
reason why it will not work on stock thicker than 0.035 in. 

The small wear of cast iron, even in its natural state, indicates 
that cast-iron dies might be made in large quantities at the 
foundry by inserting chills the shape of the blank. Perfora- 
tions, if any, must, of course, be made with the proper amount 
of clearance. 

Dies made by this method cost very little, the punch being of 
tool steel, as usual. A cast-iron punch and die have been used 
for experimental motor field and armature laminations, producing 
the highest type of stampings. 

A Positive Stripper. — A punch and die for piercing 144 holes 
in 20-gage iron in the location indicated in Fig. 270 was made as 
shown. As the holes were 0.2285 in. diameter and the metal 
0.0375 in. thick, the ordinary spring-actuated stripper, with the 
long punches which necessarily go with it, did not give very 
good results, so a positive stripper was used. 

In the die (not shown) the holes were located, drilled and taper 
broached for clearance in the usual way, and the holes for the 
subpress pins were bored, reamed and chamfered. The die was 



MAKING OF DIES 



181 



then hardened and the holes in the punch-holder were transferred 
from the hardened die. 

Referring to Fig. 270, A is the cast-iron punch-holder, B the 
punch pad, which was made of %-in. boiler plate, held to A by 
34-in. machine screws and located by the subpress pins which 



-OL 




Fig. 270.— Die for 144 holes. 



act as dowels. The stripper C was made of boiler plate and 
machinery steel, built up to save turning; the D punches were 
made of No. 30 drill rod, headed over as indicated, hardened in 
oil and drawn; the subpress pins E were tool steel hardened and 
ground. 



182 



PRACTICAL DIE-MAKING 



The stripper C was turned a close working fit in A and B and 
drilled and reamed a close working fit on the punches D. The 
shank of the stripper C extended 34 m - above the shank of the 
punch-holder A and was held from dropping out by a %-in. 
capscrew and washer. 

In operation the stripper came into contact with the work and 
slid up into the holder, thus supporting the punches while they 
pierced the work and entered the die. 



Punch Holder 



\ 



Fig. 271. — Using a rubber stripper. 



As the punch ascended the capscrew struck the kickout on the 
press, forcing the stripper down and thus stripping the work 
from the punches. In order to lessen the stress on the press the 
inner row of punches was %± in. shorter than the outer row, 3^2 
in. shorter than the second row and %4 in. shorter than the 
third row. 

There are other cases where a rubber stripper, as shown in Fig. 
271, is found useful. 

Force Necessary to Strip Work from Punches. — Nearly all 
shops which have much to do with punching of steel and other 
metals have their own standards for both punches and dies. 



MAKING OF DIES 



183 



But, unless they have had actual punching experience, they are 
apt to be at a loss as to the amount of taper to give the punches. 

No one who has not made actual stripping tests realizes that 
the largest percentageof punches are broken in stripping, and this 
depends largely on the taper of the punches. 

Some argue that the taper on a punch allows the metal to close 
around the punch and makes stripping harder. This does not 
seem to be borne out by tests made by H. D. MacDonald. He 
made punches with 2-degree taper, with 1-degree taper and 
straight, and punched a piece of machinery steel 2 in. wide, 2% 
in. long and % in. thick with each punch. These pieces were 
then taken to a Riehle testing machine and each stripped in 
the same way. 



j ^Parallel 




Fig. 272. — The proposed punch. 



The first punch with a 2-degree taper stripped at 550 lb., the 
second with 1-degree taper at 780 lb., and the straight punch 
required 2000 lb. All three punches were 2 %2 m - m diameter. 

This shows very clearly that the tapered punch strips more 
easily and will stand up better against breakage. On the other 
hand, it will not last as long as a straight one as it cannot be 
ground without losing its size. 

It is suggested that a punch made as shown in Fig. 272, with a 
short straight portion and tapered 2 degrees behind the straight, 
might be a satisfactory compromise. 

Suggestions for Press Tool Standards. — A simple, yet durable, 
punch and die outfit is shown in Fig. 273, which for small work 
can be easily changed from one job to another without changing 
the holders, providing the diameters of the blanks are the same or 
nearly the same. The holder a is a drop forging. The distances 
between the centers of the screw holes and the die are made to a 
standard jig. The die b is of tool steel hardened and ground, the 



184 



PRACTICAL DIE-MAKING 



taper of the dies and holders being 3 degrees. The drawing punch 
d is of tool steel hardened and ground, and e, which is the blanking 
punch, of tool steel, is also hardened and ground on the diameter 
x. The punches are secured in their respective holders by 
square-head setscrews. 



!■ 



£=) 



LP 



f 






FT 



fr — *A-#i 



=nrl 



-M- 



ED 



A 


B 


C 


D 


E 


F 


G 


H 


j 


M 


N 


% 


1 


m 


1M 


>2 


1>8 


1 


H 


« 


% 


3M 


1 


m 


m 


1H 


y% 


1 3 8 


1 X 4 


H 


y± 


% 


3M 


1% 


1H 


m 


m 


5 A 


1% 


l?i 


l 


3 8 


/8 


3^ 


m 


m 


2 


m 


H 


2H 


2 


1 '-4 


26 


Vl 


4 


m 


2 


2 


m 


l 


2H 


2H 


w 


*2 


H 


4 


2H 


2 


2 


13-2 


IVs 


2% 


2>2 


m 


1 i 


H 


4 



Fig. 273. — Die-holder sizes. 



The dies are forced into their holders, screwed to the bolster 
plate and the tops of the dies are ground in a surface grinder so 
that the metal will feed over them easily. In like manner the 



MAKING OF DIES 



185 



blanking punches are ground, while the drawing punches may be 
left as they are without grinding. 

Fig. 274 is a set of tools which may be used for work too 
large to be done with the tools shown in Fig. 273. These tools 
can be used for cutting and drawing, drawing, or drawing and 
redrawing. The die-holder a is of cast iron finished as indicated; 
b is the first die of tool steel hardened and ground in which is cut 





15°Taper 



N O P R S 



T W 



2 
2H 

3J4 
3U 

4-H 



2H 45|iH 6 ,3M 6 



2H 4^liH 6 .3M' 



H2M 6 



mi' 



1H4M| ^;2h[ihJ 1 m 
1H' 



4J4 H2H2 iM 6 



J* jw 

7 /i |H 

7 /i |>* 



7 ,i % 7 /i 



3H 



8HJ13J1H 
8H13J1H 



41/2I 2H2H1 



4^1 2U2H1 



4H 6 3 1 ?'i 



Ji 4Ji 



H131K4H1 |2Hl3H|l 



161H4^1H.3H2 1H 



2H 



5?1 6 5M 6 



161Hl4H 



16.1 1/4U 1/2 



l 1 -4 3 1 s2 : '.i li k 



1H3H3H1H 
1H,3H3?4 1H 



Fig. 274. — Die block sizes. 



the shape of the blank, or the diameter of the drawn shell. These 
dies have a 15-degree taper on a side. For cutting and drawing, 
or drawing, these dies bottom on a steel ring d which may or may 
not be case-hardened. For redrawing, another ring of the same 
dimensions as this one, except for the bore, is used, and the re- 
drawing is done with a "floating" die ^2 m - smaller in diameter 



186 



PRACTICAL DIE-MAKING 



than the bore of the ring and ^4 in. lower than the ring. The 
reason for having the redrawing die a floating die is that, should 
there be any discrepancy between the centers of the two dies, the 
drawing punch will locate the lower die so that it will have to 
come right anyway. 

At e is shown the die ring or retaining ring of tool steel, the 
taper at the inside being 15 degrees on a side to suit the taper 




r-feg 



— N--- 



t 1 ! 



A 


B C 


D 


E 


F 


G 


H 


I 


K 


M 


N 





Screw 


2H 


m 


4M 6 


M 


1 


I'M 6 


2H 


7H 


3H 


1M 


1H\ 13 3 i 


w 


H"X2" 


3H 


7 


6 


VA 


Wi 


li^e 


2A 


8H 


3*i 


13-6 


m 13H 


2J« 


W'xaw 


4J4 


7 


7 


25,16 


IA 


2M 


3H 


73/4 


3A 


1H 


1M 


133i 


3 


WX2H" 


5H 


T'A 


7A 


w 


3 


2M 


3M 


8 1/4 


4 


1M 


1H 


14 


3 


54"X8" 


6}i 


9 


9 


2 


3H 


2H 


3/2 


9 


5 


1H 


1H 


14 


3 


H"X3" 


7H 


10 U 


10 m 


2H 


4J6 
5J$ 


2' i 


4 


9?4 


5 


1H 


1M 


16' 4 


2N 


H"X3" 


8M 6 


11 n 


UH 


23,! 6 


2H 


4 


II/2 


5W 


1H 


1M 


17 


23 4 


iH«"X3" 


9H 


113/4 


11 m 


2H 8 


6 


2H 


4 


UH 


5H 


1H 


1M 


17H 


2H 


»H«"X3" 



Fig. 275. — Die block sizes. 



on the dies. The thread on these rings and in the die beds in all 
cases is 10 per inch, and four holes are drilled, as shown, to allow 
tightening. The dies when new project from ^8 to ${q in. above 
the bed and retaining ring to allow them to be ground. 

It will be seen that many sizes of shells can be blanked or 
drawn in the same bed without removing the bed from the press, 
as all rings and dies are made to a standard gage. 

Fig. 275 is a poppet bed of cast iron; the taper of the dies 



MAKING OF DIES 



187 



used is 5 degrees on a side, and they are held in place by four tool- 
steel setscrews with the ends reduced and hardened. Such beds 
are used mostly for the redrawing of shells and not for blanking. 

Laying Out Stepped Dies. — A short time ago we had to make a 
number of large dies for automobile doors. Fig. 276 shows the 
general shape of the lower half of a large subpress die used for 
piercing a number of holes in one of the doors. As the doors 
were of an irregular shape, it was necessary to have the dies 
(which were located in the bosses) of different heights to conform. 
They were all too big to clamp to an angle plate and lay out as 
we do small dies, using a height gage. 

The dies were strapped to the platen of a small planer and the 
tool A (which was simply a square piece of machine steel with a 




Fig. 276.— A stepped die. 

stiff scriber fastened in one end) was made and clamped in the 
planer tool holder. It had to be made long as shown, as the dies 
would not go between the housings. To lay out the work, a 24- 
in. scale was clamped to the rail and an index-finger, made from 
thin sheet metal, was clamped to the saddle with the end resting 
on the scale. This gave us a means of getting our dimensions in 
one direction, while another scale laid in the way with one 
end kept against the platen and a conveniently scribed zero 
mark, furnished us a way of getting our dimensions in the other 
direction. 

The rail was raised and lowered to bring the scriber into contact 
with the work and the lines were scribed by moving the platen or 
the head. A center could be established by a slight blow on the 



188 



PRACTICAL DIE-MAKING 



top of the scriber. This proved to be a quick way of laying out 
the dies, and as accurate as the work called for. 



A.) (. 



o 



o 



?& 



^7 



W 



Fig. 277. — Method of holding a punch. 

Method of Holding Punches in Place. — Combination drawing 
and reducing punches which pulled out of their holders, even when 
the screws were set up hard against tapered flats, were replaced 
by the method shown in Fig. 277. 




Fig. 278. — Another punch holder. 

A semicircular groove A was cut around the punch, while the 
clamping plate of the press gate had a similar groove B cut in it. 



MAKING OF DIES 



189 



A half-ring C of round bessemer wire was made to fit the com- 
bined half-round grooves in the punch shank and the clamp. This 
ring was then set into these grooves, and the clamp was tightened. 

Equipped in this manner a punch will hold no matter how severe 
the duty. 

Another method is shown in Fig. 278. This can also be used 
in making multiple-punch tools, where it is often necessary to 
locate the punches as close as possible to prevent handling the 
work more than once. The design shown has been found very 
efficient on heavy work. 




Fig. 279. — Method of relocating punches. 

The punch A is held in place by the threaded sleeve B, which is 
tightened up with the special wrench C. 

This arrangement also permits of any punch being removed or 
replaced without disturbing the others. 

Relocating Misplaced Punches. — An error was made in lay- 
ing out a combination, three-at-a-time piercing, shearing and 
blanking die. Instead of making a new die and punches, the 
method shown in Fig. 279 was used by the tool-room foreman: 

A correct die was made and the punches that had been sheared 
in the spoiled die were used. A piece of cast iron D, with a hole 
the same diameter as the punch shank, was bored and faced. 
A slot was milled in one side of the bottom to allow the punch E 



190 



PRACTICAL DIE -MA KING 



to be seen when in the die A. The center punch C was then in- 
serted and the punch and die brought together in the screw press 
until it marked the punch block B. It was then indicated up in 
the lathe and bored to suit the punch. This proved satisfactory 
and saved the cost of the punches. 

Chart for Deflections and Loads on Rubber Pads. — In design- 
ing a punch and die for a trimming and embossing operation, it 
was necessary to emboss before trimming; consequently the 
stripper, which was backed up by the rubber pad and stripper 



Die holder with die 
and shedder removed 




Zl 



Cum Rubber- 
._ pad or Bumper 



Fig. 280. — Rubber stripper used in tests. 



pin A, as shown in Fig. 280, had to withstand the resistance of 
embossing. 

Considerable experimenting gave the definite figures which 
have been put in the chart given in Fig. 281. 

At the left-hand side of the chart is found the deflection or 
compression of the rubber and at the bottom the corresponding 
average load or weight necessary to compress the rubber pad. 

For instance, if the rubber is to be compressed 34 in-> as is 
usually the case with a bending die, follow the horizontal deflection 
line at 34 in. until it meets the diagonal line and then follow down 
the vertical load line at this point at the bottom, and it is found 
the rubber will offer a resistance of 340 lb. 



MAKING OF DIES 



191 




EIS *>k =|£ m|» oi|sB _| N HS o mico 



192 



PRACTICAL DIE-MAKING 



Chart for Cup Blank Diameters. — A series of cup curves 
were plotted and the result is given in Fig. 285. It has been 
noticed that upon taking a blank of any diameter and drawing 
it into a number of plain cups the tops, when connected, formed a 
curve similar to those shown in the chart. 

With this as a working basis the curves were plotted for each 
3^-in. difference in blank diameter from in. to 12 in., using the 
American Machinists' Handbook formula B = \/D(D + 4#), 
which is the correct surface formula for plain cups with sharp 
corners. As this formula does not take into account the radius 
at the bottom of most drawn cups as in Fig. 282, which increases 
the height of the cup over a sharp-cornered cup of equal cup and 
blank diameters, the following formula was worked out with this 
in view: 

R(0A3D + 0.143R) 



C = 



J) 



Fig. 283. 



* 


D 


— 




->■ 














—*. 










I 


I 
Y 



K- - 



- D 

P-2R >j< 



-R-- 



k4: 



4 Rr Center 
of Gravity 



Fig. 282. 

Figs. 282 to 284.- 



Fig. 284. 
-Three cup blanks. 



'•'' iCenter of 
Crayily 



The derivation of the American Machinists' Handbook formula 
is here given as well as the height-correction formula and methods 
of using the chart : 

C = Height correction. 

H = Height. 

R = Radius. 

D = Diameter. 

B = Blank diameter. 

American Machinists' Handbook Formula 



Area at bottom of cup 
Area of shell = DirH. 



ir- 



Total area 



D 5 



+ DttH. 



MAKING OF DIES 193 

Blank diameter having this total area 



&£ + DrH 



4:DH 



v 4 

= V D{D + 4#) 

Height Correction Formula 

Area of ring section X, Fig. 283, = 2Rt(D - 0.5/2) ; 

Area of ring section F, Fig. 284, = (D - 0.728/2)tt ^^ 

Difference in area between X and Y = 2Rir{D — 0.522) — 
(D - 0.728/2) tt-^ 

The height of a shell whose diameter = D, and whose area = 
difference between X and Y 

2Rtt(D - 0.5/2) - (Z> - 0.728/2) tt ^ 



2Z2(Z) - 


Dtt 

- 0.5/2) - (D - 


- 0.728/2) 


2 


2/2/)- 


Z2 2 - 


- 1.57/2D + 1.143/2 2 




0.43/2Z) 


+ 


/) 
0.143/2 2 






5(0.431 


/) 

» + 


0.143/2) 





To illustrate the use of the chart, Fig. 285, consider the following 
examples : Having given a cup whose diameter is 4 in. and whose 
height is 8 in., with sharp corners, to find the blank diameter. 

Find the 4 in. on the cup-diameter scale and the 8 in. on the 
height scale. The intersecting curve will be found to be the 
12-in. blank curve. 

If instead of a sharp-cornered cup we have a radius of 1% in., 
it is first necessary to find what increase in height of cup this 
radius will make over a sharp-cornered cup 4 in. in diameter. It 
will be found that the 1^-in. radius line will fall 2 %2 m - (scaled) 



194 



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MAKING OF DIES 



195 



below the zero line, in the height correction scale at its inter- 
section with the 4-in. cup-diameter line. Deducting this 2 %2 m - 
from the 8 in. height we have 7%*2 m -> an d it will be seen from 
the chart that the new blank diameter curve will be 113^ in. 
slightly full. 

In plotting the curves mean cup sizes were considered, as shown 
in the chart, but outside cup sizes are sufficiently close, except in 
cases of very thick metal. It should also be understood that the 
cup must have a uniform metal thickness. 



Authorities Quoted 



Archer, W. E., 53 

Ball, Martin H., 1 

Barnett, Robt. T., 82 

Bingham, J., 112, 169 

Breitschmid, Geo. P., 4 

Brown, Joseph, 12 

Bruns, John N., 66 

Clerkenwell, O., 77 

Colvin, Fred H., 10, 55, 119 

Day, J. W., 96 

Doescher, Charles, 139 

Dunbar, H. W., 3 

Eike, G. W., 189 

Fay, Lawrence, 15 

Fenaux, P. P., 11 

Floyd, D., 187 

Flynt, L. W. G., 46 

Fredericks, P. A., 15, 51, 67 

Gallimore, James, 8 

Geist, B., 66 

George, W., 28 

Graham, J. C., 58 

Grannis, George R., 60, 97, 190 

Greene, Harold E., 50 

Greenleaf, W. B., 164 

Heberle, Jacob, 23 

Hilfiker, F. O., 14 

Hogg, J., 61, 91, 162 

Hollis, R. H., 42 

Horn, Harry J., 192 

Kavanagh, Thos. J., 109 

Lalle, Allen, 7 

Lawrence, W. J., 175 



124 



180 



154 



Lindholm, A. C., 83, 86 ; 
Long, George F., 188 
Long, Joseph K., 172 
Martin, M., 23, 30 
Mason, F. C., 166, 179, 
Moore, C. E., 180 
Murphy, W. J., 75 
Oestreich, B., 47 
Phillips, J. C., 33 
Remacle, Gustave A. 
Riley, G., 188 
Rogers, C. A., 6 
Ross, F. E., 173 
Scribner, C. F., 80, 94 
Sewell, J. M., 177 
Simon, George, 176 
Smith, G. R., 116 
Sprink, J. W., 40 
Stevenson, G. K., 72 
Stuart, J. C., 92 
Suverkrop, E. A., 73, 74 
Thompson, Waren E., 54, 158 
Throne, R. P., 35, 39 
Unger, P. O., 113 
Urbani-Puschmann, P. 0., 98 
Van Deventer, John H., 130 
Viall, Ethan, 48 
Vogt, Julius F. A., 150 
Walters, Ernest A., 19, 102 
Webster, J. M., 22 
Weinland, R. Earl, 36 
Wright, Mills, 1S3 



INDEX 



Adding machine dies, 6 
Adjustable dies, 42 
Aluminum cap, die for, 164 
Angle iron, tools for, 67 
Annealing stock with borax, 161 
Authorities, quoted in book, 195 
Automatic spacing device, 51 



B 



Ball bearing cones, 48 
Balls from flat stock, 109 
Bending a hook, 5, 6 

and forming dies, 1 

dies for adding machines, 6 

fixture, hard, 4 
Bicycle hub, 102 

Blanking and drawing at one stroke, 
75 

and forming die, combined, 170 

dies, 64 

cast-iron, 180 

double, 58 
Boiler tubes, upsetting, 170 
Boxes of sheet metal, 86 
Brass shells, 116 

Bulldozers for drawing cartridge 
cases, 30 



Cans, dies for, 66 
Cartridge cases, 130 
Cast-iron blanking dies, 180 
Celluloid, die for, 54 
Chain block punching, 36 
Chart for cup blanks, 192 

for rubber pads, 190 
Clips, tools for, 64 
Clock plates, tools for, 139 

wheels, sub-punch for, 152 



Clocks, press tools for, 139 
Combined blanking and forming 

die, 176 
Copper shells, 124 
Cup blank diameter, 192 
Curling chuck, 30 

tools, 28, 33, 60 
Curtain bracket dies, 162 
Curved shell, drawing, 74 
Cutting off angle iron, 67 

two blanks at each revolution, 
58 

D 

Deep drawing of metals, 113 
Dies, adjustable, 42 
Difficult dies made easily, 179 
Door knobs, tools for, 112 
Double operation die, 169 
Drawing brass shells,' 116, 124 

curved shell, 74 

deep, 113 

18 lb. cartridge cases, 130 

pressure required for, 119 

punch and die, 80 

sheet metal, 70 



Economical dies, 162 
Eyeglass bridges, tools for, 158 
Eyes, forming in wire, 11 



Fan hub-pressed steel, 82 
Fastening punches in place, 188 
Fiber washer, punch for, 53 
Flasks, tool for oval, 77 
Force to strip work from punches, 

182 
Forgings, hot punchings of, 54 



197 



198 



INDEX 



Forming a clip, 15 

a sheet metal roll, 15 

die, economical, 175 

eyes in wire, 11 

handles, 8, 10 

rings in punch press, 12 

tubes, 19, 22 
Fuse clip, 83 



Grates, tools for perforating, 150 



II 



Hand bending fixtures, 4 

punch, multiple, 52 
Heading staybolts, 172 
Holding punches, methods of, 188 
Hollow balls from flat stock, 109 

shafts, pressed-steel, 99 
Hook, bending a, 5, 6 
Hot bending a hook, 6 

punching of forgings, 54 
Hub for bicycle, 102 



K 



Knobs, tools for door, 112 



Positive stripper, 180 
Press tool standards, 183 

tools for clocks, 139 
Pressed steel pulley, 78 
for hub, 82 

vs. machine-finished parts, 98 
Pressure required for drawing, 119 
Progressive drawing, piercing and 

blanking dies, 166 
Pulley, one piece steel, 78 
Punch for wrench, 47 
Punches, methods of holding, 188 

multiple, 24 

relocating, 189 

stripping work from, 182 
Punching die, sectional, 173 

holes in chain blocks, 36 

small holes in tubes, 23 



Ratchets, punch and die for, 49 
Reinforcing for tapped holes, 94 
Relocating punches, 189 
Right angle bends, 3 
Rings, forming in punch press, 12 
Rivets formed in sheet metal, 72 
Roll, forming a sheet metal, 15 
Rubber pad, deflections of, 190 



M 



S 



Multiple hand punch, 52 
punches, 24 



Oval flasks, tools for, 77 



Perforating dies for round shells, 39 
Piercing, blanking and forming die, 

40 
Pillar-press tools, 139 
Planers for drawing cartridge cases, 

130 



Seaming die, 35 
Sectional die, 177 

punching dies, 173 

subpress die, 154 
Shearing in punch press, 46-48 
Shell perforating, 39 
Shells, blanking and drawing, 75 

brass, 116 
Small forming die, 92 
Spacing device, automatic, 51 
Standards for press tools, 183 
Staples, tools for, 61 
Steel tube, making in press, 19 
Stepped dies, laying out, 187 
Stripper, a positive, 180 
Stripping work from puncher, 182 



INDEX 



199 



Subpress die, sectional, 154 
for clock wheels, 152 
perforating dies, 150 

Swivel, tools for, 91 



Upsetting boiler tubes, 170 
staybolts, 172 



Thick blanks, tools for, 66-73 
Tube, punching small holes in, 23 
Tubes, upsetting boiler, 170 
Typewriter frame punch, 60 



W 

Wire handles, 8, 10 

Wiring sheet metal buckets, 23 

Wrenches, punch for two, 47 




w 

(fflmm 

nf/i/ff/H 



